* Johnson's spokesman spoke at gathering
* Conservatives lose lead in YouGov poll
* Second poll shows Labour ahead
* Lockdown party scandal hits Johnson
* Johnson faces rebellion from own lawmakers

British Prime Minister Boris Johnson faced mounting pressure on Friday after his Conservatives lost their poll lead over Labour and it was revealed that his chief spokesman attended a festive gathering in Downing Street during a lockdown last year.
Johnson, who won a landslide victory in a 2019 election, has faced a barrage of criticism since a video emerged showing his staff laughing and joking about a Downing Street party during a 2020 Christmas lockdown when such festivities were banned.
Downing Street had denied a party took place. Johnson said he was furious about the impression that the video gave that there was one rule for those at the heart of British power and another for the people.
Johnson told parliament on Wednesday that he had been assured Covid rules were not broken and that there had been no party. He has asked Britain's most senior civil servant, Cabinet Secretary Simon Case, to investigate.
But broadcasters ITV and the BBC reported that Johnson's most senior communications adviser, Jack Doyle, had made a speech and handed out awards as part of a joke ceremony at an alleged party on Dec. 18 last year.
Downing Street declined comment. Doyle, who at the time of the alleged party was deputy director of communications, did not immediately respond to a request for comment.
Johnson, 57, has faced criticism in recent months over his handling of a sleaze scandal, the awarding of lucrative Covid contracts, the refurbishment of his Downing Street flat and a claim he intervened to ensure pets were evacuated from Kabul during the chaotic Western withdrawal in August.
Opposition parties have accused him of lying and being unfit for office, and some have called on him to resign.
As he grappled with the furore, his Conservative Party lost its poll lead over the opposition Labour Party and dozens of his own lawmakers prepared to rebel over new Covid rules.
A YouGov poll for The Times newspaper showed Johnson's Conservatives had dropped 3 percentage points from Dec. 2 to 33% of the vote while Labour rose 4 percentage points to 37%.
Three quarters of people believe that there was a Christmas party in which coronavirus rules were broken and 68% of those polled believe Johnson was not telling the truth when he denied it, The Times said.
Another Survation poll of 1,178 people carried out on Wednesday and Thursday put Labour on 40% of the vote, up 1 percentage point, and Johnson's Conservatives down 2 to 34%.
At the time of the Downing Street gathering, people across Britain were banned from meeting close family or friends for a traditional Christmas celebration - and even from bidding farewell to dying relatives. Nearly 146,000 people have died from Covid in the United Kingdom.
Johnson imposed new Covid restrictions on England on Wednesday, angering the libertarian wing of his party.
Dozens of Conservative lawmakers are planning to oppose the new rules in a vote in parliament next week.
"I expect a record number of Conservative MPs to vote against these latest restrictions," said John Redwood, a Conservative lawmaker.
Johnson won 365 of 650 seats in the 2019 snap election, the biggest Conservative Party majority since Margaret Thatcher's 1987 victory, on a pledge to take Britain out of the European Union.