David Cameron was branded a coward last night for refusing to debate on TV with senior Brexit campaigners.

Despite claiming the case to stay in the EU is overwhelming, the Prime Minister will take part only in interviews and question and answer sessions with voters.

His opponents suspect he fears a clash over open borders when thousands of migrants are heading across the Mediterranean to Europe.

EU border officials say a deal with Turkey to control the flow into Greece is working – with numbers down 90 per cent. But yesterday Italy said it had rescued more than 2,600 migrants from the sea in just 24 hours.

On their way: Migrants make the sea crossing from Libya to Italy. EU officials have warned that up to 500,000 could use the Mediterranean route into Europe this year

Plucked to safety: Some of the migrants picked up off Libya. Eight pregnant women were among them

The overwhelming majority were searching for a better life rather than fleeing war or persecution.

Iain Duncan Smith accused the Government of trying to fix the June 23 referendum and stifle debate. ‘The refusal to engage in a fair contest is the definition of cowardice,’ said the Leave campaigner and former cabinet minister.

‘It must not be up to politicians to decide what the public sees and hears. It’s clear as day that this government is doing its level best to gerrymander the referendum and stifle debate.

‘Not only have they published reports that they brazenly admit are biased, and colluded with big business to bully staff into voting their way, they are now dictating the terms of public debate – selecting their own opponents and refusing to engage with those they deem too tough.’

Official immigration figures out tomorrow are expected to make grim reading for Mr Cameron – and confirm it is impossible to keep his promise to cut net immigration to below 100,000 while remaining within the EU’s free movement rules.

Mr Cameron has now dodged a confrontation with Justice Secretary Michael Gove and ducked the chance to take on former London mayor Boris Johnson in the final TV showdown – a BBC-hosted debate 48 hours before polling day.

Defence secretary Michael Fallon may now take his place.

No 10 is said to have issued an ultimatum to broadcasters, warning that Mr Cameron would rather sit out their programmes than debate the merits of the EU with a senior figure from the Brexit camp on live TV.

As the referendum campaign entered its final month:

The Prime Minister insisted his party would ‘come together’ after the poll despite talk of a plot to topple him;

He risked further enraging Tory MPs by claiming that a vote for Brussels was the ‘patriotic’ option;

Twelve former military chiefs argued that our armed forces would be more effective outside the EU;

The Bank of England governor came under fire over his warnings that Brexit could cause a recession;

The Remain campaign was accused of patronising younger voters after producing a puerile video.

Mr Cameron’s TV clashes will now take place in carefully controlled circumstances.

He has agreed to an ITV debate with Ukip leader Nigel Farage on June 7, in which they will each field questions during separate segments of the same hour-long show.

Sky News has agreed a similar format, in which both Mr Cameron and Mr Gove will be grilled in shows that will be screened 24 hours apart next week.

The BBC will then hold a special edition of Question Time with Mr Gove on June 15, when he will take questions from a studio audience. But Mr Cameron’s response will come in a separate show to be broadcast four days later in which he too will field questions from the general public.

Jacob Rees-Mogg, a Brexit campaigner, said: ‘It’s no good for the Prime Minister to predict World War Three and then not be willing to defend the issue.’

David Cameron was branded a coward last night for refusing to debate on TV with Brexit campaigners

Fellow Tory MP Bernard Jenkin accused Mr Cameron of running for cover, adding: ‘He can’t answer the question why UK taxpayers have to give billions of pounds to our EU competitors when our public services are desperate for money back home.’

Lord Tebbit said the Prime Minister was avoiding a debate because he thought the campaign had already been won.

‘Personally I’d take on all comers, but David Cameron has chosen not to be directly challenged as he thinks it’s a better way for him,’ said the Tory grandee.

‘He’s using a great deal of self-protection measures. He thinks he is well ahead, he thinks his opponents are all being scared and he doesn’t want the risk of making a mistake in a debate.’

A No 10 source said the Prime Minister was right to face questions from members of the public as this was ‘seen to be an effective format during the election campaign’.

Tory backbencher Stewart Jackson said revelations in yesterday’s Daily Mail that Mr Cameron is set to face a vote of no confidence from his own backbenchers, were ‘spot on’.

Mr Cameron’s former policy guru, who has fiercely criticised the campaign to keep Britain in the EU, suggested Mr Cameron did not want to risk a TV debate because he felt his side was ahead in the polls.

But Steve Hilton warned Tory MPs not to depose Mr Cameron, saying it would be ‘profoundly undemocratic and wrong’.

He said that it was ‘nuts’ to suggest the Prime Minister could not continue in Downing Street beyond June 23, even if voters rejected his argument at the ballot box.

Tony Blair said Mr Cameron was right to warn of ‘the risk to Britain, its economy, its position in the world’ of quitting the Brussels club.

The former PM also suggested he may be forced out of office early in the same way that he was. Asked what Mr Cameron could do to prolong his time in power, Mr Blair said: ‘It doesn’t matter what you do… there comes a point in time when it’s difficult.’

Meanwhile the Institute for Fiscal Studies claimed leaving the EU could save Britain £8billion a year, although this gain could be outweighed by the impact of lower growth.

Business as usual: Brussels says migrant numbers have plunged after a deal with Turkey. But thousands are still coming in through Italy

By John Stevens, Europe Correspondent for the Daily Mail

Thousands of migrants have poured into Europe this week, heralding the start of another summer of chaos on the continent.

The fresh influx – into Italy – comes after the EU negotiated a controversial £4.7billion deal with Turkey to ease the pressure of migrants arriving in Greece.

Two weeks ago the EU said that the number crossing the Aegean Sea to the Greek islands had fallen by 90 per cent since Turkey agreed to take them back.

A woman is helped by rescuers during an operation at sea of migrants with the Aquarius, a former North Atlantic fisheries protection ship now used by humanitarians SOS Mediterranee and Medecins Sans Frontieres

Rescued: Refugees sit on a boat during a rescue operation of migrants and refugees at sea of the Aquarius

CUTTING MIGRATION 'WOULD NOT WRECK ECONOMY' By Ian Drury, Home Affairs Correspondent for the Daily Mail Curbing immigration after a Brexit would be unlikely to cause huge damage to the economy, a report said yesterday. Experts said significant restrictions on foreigners would, if all else remained the same, only have a ‘modest’ effect on GDP per capita – the output per person. If Britain left the EU, reduced tax revenues from migrants would cause government spending to rise by between 0.4 per cent and 1.1 per cent, the National Institute of Economic and Social Research (NIESR) said. It means that by 2065, taxes would need to have increased by as little as £225 per person – or at the most £402 – to fill the shortfall. Dr Katerina Lisenkova, a senior research fellow for the NIESR, said: ‘We are not going to say that Brexit will lead to a recession.’ The study appeared to undermine doomsday claims by Remain supporters – including the Prime Minister and Chancellor – that voting to leave the Brussels club would inflict catastrophic damage on the UK economy. An analysis published by Downing Street this week warned that quitting the European Union would cost 820,000 jobs and plunge the UK into recession – claims ridiculed by the Leave campaign. But while the NIESR think-tank said post-Brexit curbs in migration would have a negative effect on the economy and lead to tax rises, it steered clear of branding it disastrous. Researchers said the impact would be ‘significant... [but] not quantitatively large and would take a long time to materialise.’ The study, hailed as the most comprehensive analysis of the long-term effect of immigration on the UK economy, compared Leave and Remain scenarios for migration after the June 23 referendum. They took the Leave campaign’s claim that net migration from the EU – those arriving minus those leaving – would fall to 92,000 a year. By 2065, curbs on migration would lead to GDP – the total size of the economy – falling by 9 per cent, the report said. But, crucially, GDP per person would only be a ‘modest’ drop of, at most, 1.1 per cent. But Dr Lisenkova added that the report did not take into account ‘negative externalities’ resulting from migration, such as the potential social impacts on schools, health services and housing. Tony Blair yesterday defended the last Labour government’s open door immigration policy. The 2.2million EU-born workers currently in the UK is 1.4million up on 2004 when he threw open the UK’s doors to Eastern Europe by axing employment restrictions. Speaking at an event in London, the former prime minister said arrivals from Europe had contributed much more than they had ‘taken away’ in benefits. He said he ‘did not accept’ that he had let in too many migrants. Advertisement

But at the same time the number attempting the more perilous crossing from North Africa into Italy is rising as the weather begins to warm up.

Italy revealed yesterday that it had rescued more than 2,600 migrants in only 24 hours.

The country’s coastguard said they had helped save 2,000 off the Libyan coast from 14 rubber dinghies and one larger boat on Monday.

Another 636 were rescued from two boats in Maltese waters, in operations involving Maltese and Italian vessels, it said. It gave no information about the nationalities of those saved.

Libyan coastguards yesterday detained a further 550 people trying to reach Europe illegally by boat. Authorities said those intercepted from four large inflatables were from ‘several African countries’ and included three children and 30 women, eight of whom were pregnant.

EU officials have warned that up to half a million more migrants will arrive from Libya alone this year, reigniting the crisis as the continent struggles to cope with the consequences of German chancellor Angela Merkel’s decision to let in more than a million last year.

And despite the deal with Turkey, the country’s president is threatening to open the floodgates again in a row with Brussels over travel rules for Turks wanting to go to Europe.

Taken to safety: Rescuers transport refugees and migrants during an operation at sea with the Aquarius

Women and children are rescued during an operation in the Mediterranean sea in front of the Libyan coast

The overwhelming majority attempting the crossing from North Africa are economic migrants rather than genuine refugees from Syria or Iraq.

In Libya the chaos since Muammar Gaddafi’s overthrow in 2011 has been exploited by people traffickers, with thousands of migrants trying to reach Europe.

Most of those trying to reach Italy, which is 190 miles from Italy, leave the coast of Libya on rickety fishing boats or rubber dinghies, heading for the Italian island of Lampedusa, which is close to Tunisia, or towards Sicily.

The onset of better weather has raised fears of huge numbers attempting the still perilous sea crossing.

Increased patrols in the Mediterranean appear to have convinced many migrants they will be rescued before they get into any difficulties at sea.

So far this year more than 34,000 people have been brought to the Italian coast after being rescued off Libya, according to the United Nations High Commission for Refugees. A further 156,000 have landed in Greece.

According to forecasts by the International Organisation for Migration, Italy appears on track to take in at least 100,000 migrants from North Africa across the Mediterranean for the third straight year in 2016.

An IOM spokesman said current trends are following last year, when a surge of people crossed from North Africa during the summer months.

He said: ‘The numbers each month so far this year have been almost identical to those in 2015.

In need of help: Refugees wait to be rescued in the Mediterranean sea in front of the Libyan coast

550 migrants from sub-Saharan Africa were picked up today after they set out to cross the Mediterranean in four rubber boats, Tripoli coastguard spokesman Ayoub Qassem said

‘The arrivals look likely to be robust again through the warmer months.

‘There have been concerns that the closure of the route from Turkey to Greece will lead to people crossing from North Africa instead.

‘We have seen no evidence of that so far but it is such a long journey that is too early to say whether there is a shift.’

Austria has begun building a fence on its border with Italy at the Brenner Pass through the Alps because of concerns.

LEAVING THE EU COULD SAVE US £8BILLION A YEAR Brexit could provide Britain with an annual £8billion ‘independence dividend’ – though it could also extend austerity by two years, a leading think-tank claims today. The Institute for Fiscal Studies acknowledges that leaving the EU ‘could directly free up about £8billion a year, which is the UK’s likely net contribution to the EU budget over the next few years.’ But the think-tank also warns that these savings could be outweighed by the cost of slower economic growth. It claims that Britain’s gross domestic product could be up to £40billion lower by 2020, wiping out any financial savings and knocking the Government’s austerity drive off track. IFS director Paul Johnson said: ‘Getting the budget to balance from there, as the Government desires, would require an additional year or two of austerity at current rates of spending cuts.’ Shadow Chancellor John McDonnell said the figures showed that ‘Tory Brexit’ would be ‘a disaster for the UK’. But energy minister Andrea Leadsom accused the IFS of ignoring the increased trading opportunities that could be opened up by a Brexit vote. Advertisement

Italy is calling for floating migrant processing centres to be stationed in the Mediterranean to register all arrivals before they reach land.

Greece yesterday sent in police and bulldozers to knock down tents and relocate thousands of migrants who have been stranded for months in a squalid camp on the border with Macedonia.

In an operation that began shortly after sunrise, officers put more than 1,500 people on buses to newly opened camps near Greece’s second city Thessaloniki, about 50 miles to the south.

Officials said it would take at least ten days to clear all 8,400 people living in the makeshift, overcrowded and muddy camp at Idomeni.

At its height, more than 12,000 people were crammed into the camp which aid groups opened last year to accommodate 2,500 people during what was, at the time, a short procedure to cross the border.

But it exploded in size after Balkan states began closing their borders in mid-February to stem the human tide seeking passage to northern Europe.

The IOM yesterday said fewer migrants are dying as they try to cross the Mediterranean to Europe because rescue operations have been stepped up.

So far this year 1,370 migrants and refugees have died at sea, nearly 25 per cent fewer than in the same period last year.

Meanwhile Europe has accused United Nations aid workers in Greece of inciting people there to apply for asylum even if they have no chance of getting it.

At a meeting of European Commission officials in Brussels, the Daily Mail has learnt, first vice president Frans Timmermans blamed them for disrupting the deal with Turkey to ease the crisis.

He said the UN refugee agency workers on the Greek islands, such as Lesbos, were creating problems by encouraging migrants to ‘submit asylum requests when they quite blatantly did not meet the requirements to apply for refugee status’.