* Extension could last until January, March or mid-2020
* EU budget talks in second half of 2020 seen a red line
* EU leaders will discuss delay at Oct.17-18 summit
* Key risk seen in Johnson's reluctance to request one
* Despite French misgivings, EU wants to avoid no-deal blame
By Gabriela Baczynska
BRUSSELS, Sept 26 (Reuters) - A damning UK Supreme Court ruling against British Prime Minister Boris Johnson this week has rekindled discussion within the European Union about another delay to Brexit, with the bloc drawing a line in the sand of mid-2020 at the latest.
The British parliament resumed on Wednesday after the court ruled that the chamber had been unlawfully suspended by Johnson, who insists he will take Britain out of the EU on Oct.31 - with or without a deal to manage the fallout.
But British lawmakers reject the most damaging, no-deal Brexit and, back at work, will now have more chance to upset Johnson's plans.
With the divorce deal stalled, the EU is expecting another delay to Britain's departure date after it was already postponed twice from the original March deadline.
"We are in favour of an extension if we also see what is the way forward, will there be a general election, a second referendum, will there be a Withdrawal Agreement," said Guy Verhofstadt, an EU lawmaker dealing with Brexit.
"I think that there is unanimity...to say 'OK, let's go forward with an extension if there is a clear path to a solution and unwinding of the situation we have today'," he told EU lawmakers on Wednesday afternoon.
With a national election expected in Britain by the end of the year, the bloc currently sees that as the most likely justification of anther lag - a decision that would require the unanimity of the 27 states staying on.
The problem is, however, that Britain would need to request such an extension, which Johnson vows never to do and EU Brexit watchers speculate about him possibly stepping aside to let someone else make the step.
Under the law, the EU could also formally demand a delay - which Britain would need to agree to for it to take effect.
But diplomats and officials dealing with Brexit in the bloc's hub Brussels ruled out such a possibility, saying it would risk feeding Johnson's rhetoric about distant elites trying to frustrate the will of the people.
SHORT OR LONG?
With many question marks over the fate of Brexit lingering three years since Britons voted out, EU leaders meeting in Brussels on Oct.17-18 will discuss the desirable length of any such delay.