Sir Keir Starmer’s plans to quickly strike a defence and security deal with the European Union have been reportedly slapped down by senior figures in the bloc.

Nick Thomas-Symonds, appointed by Mr Starmer as Minister for European relations, told EU diplomats during early meetings last month that he was aiming for substantive negotiations over a defence and security pact to last into the spring of next year, the Telegraph wrote.

But the timeline appears to be too optimistic, particularly as senior positions within the European Commission and European Council will be finalised only in the autumn, making it unlikely for any significant diplomatic work and decision to be taken before then.

Moreover, the EU reportedly has a lack of clarity on what London wants to get out of a new round of talks, which adds to the timeline.

An EU diplomat told the Telegraph: “It’s an ambitious timeline and stuffing all kinds of things into a security pact isn’t going to make it easier.

“From the EU side, taking this step by step on areas of common interest is the way to go. There is still a lot of Brexit-PTSD going around here. Let’s not overburden ourselves and ruin the good thing we got going since the Windsor Agreement [on Northern Ireland].”

Just days after his arrival in No10, Mr Starmer promised to “reset” the UK’s links with the EU during a high-profile summit held at Blenheim Palace in Oxfordshire.

Attended by EU country leaders and officials, the summit signalled Mr Starmer’s desire to draw a line under years of difficult relations following the Brexit vote.

Yet, despite having previously campaigned for a second Brexit referendum, Mr Starmer has stressed he will not bring Britain back into the 27-strong bloc.

During the summit, Mr Starmer put immigration and border security at the forefront of his agenda, calling for Europe-wide collaboration. Security around the continent was also discussed in light of a growing threat from Russia and the ongoing war at the EU’s doorsteps, in Ukraine.

A European Commission spokeswoman told the Telegraph: “The EU is committed to a positive agenda with the UK, based on the full respect and the faithful and timely implementation of the Withdrawal Agreement, including the Windsor Framework, and the Trade and Cooperation Agreement, which are the cornerstone for the EU-United Kingdom relationship.”