Theresa May’s Brexit launch suffered a series of heavy blows after key planks of her opening strategy were point-blank rejected by Europe’s top politicians.

German chancellor Angela Merkel publically dismissed her plan to begin talks on a lucrative trade deal, saying negotiations on Britain’s EU divorce – including a bill potentially hitting €60bn – must come first.

European Parliament negotiator Guy Verhofstadt then brushed off what was described by others as Ms May’s “blatant threat” to withdraw British terror and crime-fighting co-operation, in order to extract a good trade deal.

Asked if he thought Ms May was engaged in "blackmail", the European Parliament's co-ordinator for Brexit said: "I try to be a gentleman, so towards a lady I don't even use or think about the word 'blackmail'."

Back in London the Prime Minister was accused of souring the fledgling Brexit talks with her attempt to tie pan-European security collaboration to any deal.

The fallout followed the delivery of Ms May’s historic letter to President of the European Council Donald Tusk, officially notifying him of the UK’s intention to trigger Article 50 and quit the bloc.

Ms May was speaking in Parliament as Britain’s Ambassador to the EU Sir Tim Barrow personally passed the letter to Mr Tusk in Brussels at 12.20pm.

While some Tory Brexiteers beamed in the Commons, the Chamber was uncharacteristically staid as the Prime Minister told the country to not “face to the past and believe it can’t be done”, but instead trust in “the enduring power of the British spirit”.

After receiving the letter in front of a display of Union Jack and EU flags, Mr Tusk spoke of his sorrow at Europe’s rupture, telling Britain “we already miss you”.

Merkel derails May's plan for Brexit by rejecting parallel trade talks

But the grief quickly gave way to the harsh realities of the European negotiating table, as Ms Merkel poured cold water on one of her British counterpart’s key demands.

Speaking to reporters in Berlin, the German leader said negotiations on British divorce terms would take place first and that only then could the much-desired UK-EU trade talks take place.

She said: “The negotiations must first clarify how we will disentangle our interlinked relationship... and only when this question is dealt with, can we, hopefully soon after, begin talking about our future relationship.”

In her letter to Mr Tusk, the Prime Minister underlined several times how the UK believes “it is necessary to agree the terms of our future partnership alongside those of our withdrawal from the European Union”.

Theresa May announces the triggering of Article 50

Concurrent negotiations would make it easier for Ms May to secure trade terms before the UK drops out of the EU at midnight on March 29 2019.

But the force of the EU’s negotiating position, often denied by Brexiteers, was clear as the European Council stood with Ms Merkel in emphasising that divorce terms must be settled first.

That means Britain may be pushed into agreeing to settle its financial “obligations” to Brussels, which may reach €60bn by some estimates, before it can begin to talk about a trade deal that will help secure the country’s economic future.

Ms May had softened some of the language in her Article 50 letter and statement to the Commons, following her January Lancaster House speech which saw her warn she would leave the EU with “no deal” if she did not get what she wanted.

'We already miss you': Donald Tusk after receiving Article 50 letter

But her apparent attempts to be more amenable were overshadowed by her perceived threat to withdraw security co-operation from Europe.

Her Article 50 letter to Brussels repeatedly tied security links to any future agreement and warned that the “fight against crime and terrorism would be weakened” if one cannot be struck.

Downing Street officials later said the Prime Minister was merely making “a simple statement of fact” that if no deal is reached, it would mean existing arrangements on security co-operation would lapse.

They said she was referring only to co-operation linked to EU membership like the European Arrest Warrant and shared databases, while Home Secretary Amber Rudd pointed out that the UK is the largest contributor to the pan-European crime-fighting agency Europol.

Sources underlined that the PM’s words were not referring to intelligence sharing that takes place bilaterally between agencies or military aid provided to Eastern Europe through Nato, but raising security as an issue still provoked a response.

Mr Verhofstadt said: “What we shall never accept is that there is a trade-off between the one and other.

“Saying, oh, we can do a good deal on security – internal and external – but there is also a deal that we want on trade and economics.

“I think the security of our citizens is far too important to start a trade off from one to the other.”

How Brexit affected Britain's favourite foods from Weetabix to Marmite Show all 8 1 /8 How Brexit affected Britain's favourite foods from Weetabix to Marmite How Brexit affected Britain's favourite foods from Weetabix to Marmite Weetabix Chief executive of Weetabix Giles Turrell has warned that the price of one of the nation’s favourite breakfast are likely to go up this year by low-single digits in percentage terms. Reuters How Brexit affected Britain's favourite foods from Weetabix to Marmite Nescafé The cost of a 100g jar of Nescafé Original at Sainsbury’s has gone up 40p from £2.75 to £3.15 – a 14 per cent rise—since the Brexit vote. PA How Brexit affected Britain's favourite foods from Weetabix to Marmite Freddo When contacted by The Independent this month, a Mondelez spokesperson declined to discuss specific brands but confirmed that there would be "selective" price increases across its range despite the American multi-national confectionery giant reporting profits of $548m (£450m) in its last three-month financial period. Mondelez, which bought Cadbury in 2010, said rising commodity costs combined with the slump in the value of the pound had made its products more expensive to make. Cadbury How Brexit affected Britain's favourite foods from Weetabix to Marmite Mr Kipling cakes Premier Foods, the maker of Mr Kipling and Bisto gravy, said that it was considering price rises on a case-by-case basis Reuters How Brexit affected Britain's favourite foods from Weetabix to Marmite Walkers Crisps Walkers, owned by US giant PepsiCo, said "the weakened value of the pound" is affecting the import cost of some of its materials. A Walkers spokesman told the Press Association that a 32g standard bag was set to increase from 50p to 55p, and the larger grab bag from 75p to 80p. Getty How Brexit affected Britain's favourite foods from Weetabix to Marmite Marmite Tesco removed Marmite and other Unilever household brand from its website last October, after the manufacturer tried to raise its prices by about 10 per cent owing to sterling’s slump. Tesco and Unilever resolved their argument, but the price of Marmite has increased in UK supermarkets with the grocer reporting a 250g jar of Marmite will now cost Morrisons’ customers £2.64 - an increase of 12.5 per cent. Rex How Brexit affected Britain's favourite foods from Weetabix to Marmite Toblerone Toblerone came under fire in November after it increased the space between the distinctive triangles of its bars. Mondelez International, the company which makes the product, said the change was made due to price rises in recent months. Pixabay How Brexit affected Britain's favourite foods from Weetabix to Marmite Maltesers Maltesers, billed as the “lighter way to enjoy chocolate”, have also shrunk in size. Mars, which owns the brand, has reduced its pouch weight by 15 per cent. Mars said rising costs mean it had to make the unenviable decision between increasing its prices or reducing the weight of its Malteser packs. iStockphoto

Chair of the Commons Home Affairs Committee Yvette Cooper said withdrawing security cooperation would be “an act of self-harm”, adding: “She should not be trying to use this as a bargaining chip in the negotiations.”

Labour leader Jeremy Corbyn denounced Ms May's plans as “both reckless and damaging”, but Liberal Democrat leader Tim Farron went further branding the move “shameful” and a “blatant threat” that would “backfire”.

“With growing terrorist threats from around the world, it is imperative that we work together with European allies for our mutual security. She is prepared to put the safety of British and European citizens on the line just so she can deliver her hard Brexit,” he said.

Ex-attorney general and Tory backbencher Dominic Grieve, a leading supporter of the Open Britain campaign, said: “It is in Britain’s vital national interests that we retain, and even strengthen, our security cooperation with the EU after Brexit.”

Tens of thousands take to streets to demand Brexit be reversed

Ms May’s letter also shed light on her approach to Brexit, as she said she expected there to be a significant increase in the powers of devolved assemblies as a result of any deal.

She added that she could seek “implementation periods” for different parts of any deal, later expanding in an interview that it may mean the continuation of some elements of free movement and the jurisdiction of the European Court after 2019.

The Prime Minister explained that “financial services” and “network industries” that rely on supply chains and the movements of parts, such as the automotive sector, would be a priority.