Boris Johnson has sent a request to the EU for a delay to Brexit - but without his signature. The request was accompanied by a second letter, signed by Mr Johnson, saying he believes a delay would be a mistake. The PM was required by law to ask the EU for an extension to the 31 October deadline after losing a Commons vote. EU Council President Donald Tusk tweeted that he had received the extension request and would consult EU leaders "on how to react". Earlier, Mr Johnson rang European leaders, including Mr Tusk, to insist that the letter "is Parliament's letter, not my letter". Opposition MPs have warned the PM that if he tries to circumvent Parliament's instructions to seek a delay, then he may find himself in the law courts. Mr Johnson has vowed to press ahead with the legislation to implement his deal next week, but Labour says it will seek to amend it - to add additional measures on issues like workers' rights and environmental protections. Shadow chancellor John McDonnell told Sky News Sophie Ridge the prime minister could "well be in contempt of Parliament or the courts" by sending a second letter to the EU that "contradicted" the first. Legal debateThe PM has previously said he would "rather be dead in a ditch" than ask the EU to delay Brexit, and the UK would leave on 31 October "do or die". But hours after losing a crunch vote in a historic Saturday session in the House of Commons, the prime minister ordered a senior diplomat to send an unsigned photocopy of the request for a delay, which was forced on him by MPs last month. The second letter from Mr Johnson - signed off this time - makes clear he personally believes a delay would be damaging. It says the government will press on with efforts to pass the revised Brexit deal agreed with EU leaders last week into law, and that he is confident of doing so by 31 October. A cover note from Sir Tim Barrow, the UK's representative in Brussels, explained the first letter complied with the law as agreed by Parliament. BBC political editor Laura Kuenssberg described the decision to send three documents as "controversial", predicting "there will be a fight about whether Boris Johnson is trying to circumvent the court". "This is heading straight for the court, and it may very quickly end up in the Supreme Court," she added. Asked on BBC Breakfast whether the PM's move was "childish, Conservative Brexiteer MP Nigel Evans said: "Well he was going to be criticised if he didn't send the letter, because it would have been against the law." He added that "it's not all in our gift", and that EU leaders may look at both letters and deny the request for a delay. "The UK Permanent Representative will... submit the request mandated by the EU (Withdrawal) (No.2) Act 2019 later today. It is, of course, for the European Council to decide when to consider this request and whether to grant it. "Although I would have preferred a different result today, the Government will press ahead with ratification and introduce the necessary legislation early next week. I remain confident that we will complete that process by 31 October. "While it is open to the European Council to accede to the request mandated by Parliament or to offer an alternative extension period, I have made clear since becoming Prime Minister... that a further extension would damage the interests of the UK and our EU partners, and the relationship between us. "We must bring this process to a conclusion so that we can move to the next phase and build our new relationship on the foundations of our long history as neighbours and friends in this continent."