Research from the Vote Leave pressure group forecast the Government is to hand over around £1.2billion by 2020 on a series of “pre-accession” programmes for potential new EU member states including Albania, Macedonia, Montenegro and Serbia.

And that cash comes on top of £640million contributed by the UK to a Brussels deal with Turkey to tackle the European migrant crisis and smooth the path to Turkish membership of the EU.

Supporters of the campaign to quit the EU warned the only way to save cash was for the country to vote to cut ties with Brussels in the in-or-out referendum on June 23. And they pointed out that the £170million cost of the “accession” programmes was equivalent to half the annual bill for the NHS’s Cancer Care Drugs Fund.

GETTY Turkish PM Ahmet Davutoglu, European Union chiefs Donald Tusk (C) and Jean-Claude Juncker

Former Tory Cabinet minister Iain Duncan Smith said: “The Home Secretary was right to warn that allowing Albania, Serbia and Turkey into the EU could undermine our security.

The Home Secretary was right to warn that allowing Albania, Serbia and Turkey into the EU could undermine our security Iain Duncan Smith

“Letting them into Europe’s open border policy will make it harder for us to stop criminals and terrorists from these countries coming to the UK. “Despite these warnings, the UK Government has agreed to send them a staggering £2billion of UK taxpayer’s money to help them join the EU as quickly as possible. “This is a waste of our money and worse – it’s dangerous because it will make us less safe.

GETTY Hand-outs from the fund included £8.5million for a ‘European integration facility’ in Serbia

“In an uncertain world, it is not sensible to extend our border to Syria and Iraq. We should Vote Leave to take back control over who we let into the UK.” Senior Labour MP Gisela Stuart, another leading supporter of Vote Leave, said: “The NHS is already struggling to cope with a lack of funding and huge demand. Rather than sending money abroad to countries that want to join the EU I believe we should be spending our money on our priorities here in the UK.

“Instead of giving an extra 88 million people – more than our entire population – access to the NHS I believe it would be safer to take back control. “We should give our struggling NHS the £350million we send to the EU every week.” Earlier this week, Downing Street officials confirmed that the Government was still committed to further EU expansion and supported the possible entry of Turkey into the bloc. But “leave” campaigners have raised concerns that further EU enlargement will open Europe’s borders to another surge of migrants.

GETTY Former Cabinet minister Iain Duncan Smith slammed the ‘waste’ of money