THERESA May has told MPs it is their "national duty" to pass a Brexit deal after withdrawal from the EU was again pushed back.

Addressing the Commons after the EU offered the UK a six-month Brexit delay until October 31, Halloween, the Prime Minister said Parliament needed to come together for the national good.

May said agreeing a deal was the only way to avoid the UK holding European Parliament elections on May 23.

READ MORE: Tories call for May to go as Brexit delayed until Halloween

The Prime Minister told MPs: "We need to resolve this. So that we can leave the European Union with a deal as soon as possible.

"This is our national duty as elected members of this House – and nothing today is more pressing or more vital."

May said Brexit talks with the EU had been "difficult" but she had fought Britain's corner.

The Prime Minister said: "The discussions at the council were difficult and unsurprisingly many of our European partners share the deep frustration that I know so many of us feel in this House over the current impasse."

May said, if agreement on a deal could not be reached, the Government will put alternatives to MPs in a series of votes and would abide by the result.

She said: "I hope that we can reach an agreement on a single unified approach that we can put to the House for approval.

"But if we cannot do so soon, then we will seek to agree a small number of options for the future relationship that we will put to the House in a series of votes to determine which course to pursue.

"And as I have made clear before, the Government stands ready to abide by the decision of the House.

"But to make this process work, the Opposition would need to agree to this too."

The PM said: "I welcome the discussions that have taken place with the Opposition in recent days – and the further talks which are resuming today.

"This is not the normal way of British politics – and it is uncomfortable for many in both the Government and opposition parties.

"Reaching an agreement will not be easy, because to be successful it will require both sides to make compromises.

"But however challenging it may be politically, I profoundly believe that in this unique situation where the House is deadlocked, it is incumbent on both front benches to seek to work together to deliver what the British people voted for."

The National:

SNP Westminster leader Ian Blackford pushed May to reveal if a second referendum had been offered during compromise talks with Labour.

May replied: "The Government has not offered a second referendum. Our position on that issue has not changed."

The PM said the European Council had reiterated that the Withdrawal Agreement could not be re-opened.

She said: "Crucially, any agreement on the future relationship may involve a number of additions and clarifications to the Political Declaration."

May said she had argued against conditions being imposed on the UK during the delay.

The PM said she had made clear that Britain "would continue to be bound by all our ongoing obligations as a member state, including the duty of sincere co-operation".

The National:

Responding to the Prime Minister, Labour leader Jeremy Corbyn said: "The second extension in the space of a fortnight represents not only a diplomatic failure, but it is another milestone in the Government's mishandling of the entire Brexit process."

The six-month extension to October 31 was a compromise solution thrashed out by EU leaders after French President Emmanuel Macron dug-in against a longer delay lasting into 2020.

The deal has drawn sharp criticism from Tory Eurosceptics and prompted questions about how long May can stay in power.

Former Brexit secretary David Davis insisted that no progress had been made in Brussels and that pressure on May to quit as PM will increase, telling the BBC: "I think what is likely to happen is the pressure for her to go will go up.

"The pressure on her to go will increase dramatically, I suspect, now."

Commons Leader and prominent Leave backer Andrea Leadsom played down speculation that the latest delay could mean the end of Brexit.

She said: "We have to use this time to make sure that we deliver the Brexit we are all looking for, that we work closely with the EU and that they are genuinely helping to make sure we do deliver on the referendum – there won't be any changing our minds about that."

If the UK fails to take part in elections to the European Parliament on May 23-26, it will automatically leave without a deal on June 1.

A review of progress will take place at the scheduled June 20 European Council summit in Brussels, but Tusk stressed that this would be an opportunity for "taking stock" and not for any new negotiations.

The term of the current European Commission under Jean-Claude Juncker ends on October 31.

The deal stopped the clock on the UK crashing out of the EU with no deal on Friday.