MPs are tonight set to decide whether to accept a compromise deal on hunting.

The controversial Hunting Bill returns to the Commons having been amended to allow hunting under license for pest control to continue.

Frantic behind the scenes efforts are being made in Westminster to find a deal on the issue.

Labour MP Huw Irranca-Davies is set to table further amendments, toughening the Lords' position to include a ban on ban on stag hunting and hare coursing.

Peers sent the controversial legislation back to the lower House on Monday with the outright ban favoured by MPs overturned.

The Lords approved amendments to the legislation by opting to retain licensed hunting and ruling out any complete ban until 2007 at the earliest.

However many Labour MPs feel this is an affront to their constitutional supremacy as elected parliamentarians and are set to insist on a total ban being introduced in 2006.

Number 10 said on Monday the prime minister still favours a last minute compromise deal along the lines of the legislation put forward by Irranca-Davies and originally rural affairs minister Alun Michael, but rejected by his own backbenchers.

Downing Street's official spokesman said the option of allowing hunting under license remains Tony Blair's personal preference.

"He still believes that this is the best way forward, but lets wait and see what the House of Lords sends back," said the spokesman.

But environment minister Lord Whitty told peers that MPs may not accept the deal.

"I would say this House has not gone sufficiently down the road of compromise to persuade that many people within the Commons, but that is a matter for them," he said.

If there is no deal by Thursday, speaker Michael Martin is expected to invoke the Parliament Act and force through a ban.

He is understood to be satisfied that the constitutional conditions to overrule the second chamber have been met.

That could prompt mass protests by pro-hunt campaigners and open flouting of the law.