The group of MEPs claimed Boris Johnson is opting for a hard Brexit on Northern Ireland, fishing rights and Gibraltar, attempting to de-facto renegotiate the terms of the Withdrawal Agreement.
Confirming their threats to the UK, the Chair of the Environment committee of the European Parliament, Pascal Canfin, tweeted: “With the deputies of the delegation Renew EU I am co-signing this forum to support a strong European position in the face of the permanent blackmail of Boris Johnson who asks to renegotiate the Brexit agreement to hide his own mistakes.”
The warning, published on French daily Les Echos, comes as Brussels has signalled it is unwilling to cave to UK demands to discuss removing oversight by European judges from the Northern Ireland Protocol as post-Brexit negotiations continue.
The EU said a “very intense period of discussions” has begun but suggested they may not include the role of the European Court of Justice (ECJ).
Stripping the ECJ from the Brexit agreement has emerged as a key demand from the Government as it seeks to ease trade barriers between Northern Ireland and Britain.
But the EU’s proposals to slash red tape on Irish Sea trade fell short of the demand from Brexit minister Lord Frost, who is taking part in meetings in Brussels.
European Commission spokeswoman Arianna Podesta insisted the package proposed by the EU last week is extensive and that talks would not go much further than it.
Asked whether talks will include the ECJ this week, Ms Podesta told reporters in Brussels: “We are following up on the package that we have proposed on October 13 – it is a far-reaching package.”
In a statement after Friday’s Frost-Sefcovic meeting, the British government said it would discuss the EU proposals constructively and in a positive spirit.
However, Frost repeated the British view that significant changes are still required to the current arrangements, including on governance.
Further talks will continue in Brussels this week.