Hundreds of people queued outside a Coventry pub which opened at midnight as lockdown restrictions eased.
Darren Lee, owner of the Oak Inn, said 260 customers were seated in groups of up to six at its outside tables - but 300 to 400 people were turned away.
He said crowds at the Gosford Street pub were "very well behaved" and police were satisfied with the situation.
However, Coventry City Council said it was investigating to see whether it followed rules.
Shops, pub gardens, hairdressers and other venues have reopened in England, with rules also being eased in the rest of the UK.
The Oak Inn, a Marston's pub, advertised plans to open its large outdoor area, with marquees, heaters and blankets, from midnight.
Mr Lee said demand "went through the roof".
"The customers were fantastic. They supported us, they were out there in the cold. They didn't complain. It was brilliant," he said.
Mr Lee said between midnight and 04:00 BST, its normal week day closing time, the pub saw about 350 customers.
"There was probably about another 300 or 400 that we had to sadly disappoint because we couldn't get them in," he said.
Pictures of the long queue outside the pub were posted on social media prompting the council to investigate.
A spokeswoman for the local authority said with restrictions being eased it wanted to remind everyone "about the importance of following the rules", which included social distancing and regular hand washing.
Mr Lee said the council had not yet contacted him, but believed rules were observed.
"We always do things safely and properly," he said. "We were able to get outside as per the national guidelines."
Police officers who went to site were "more than happy", he added.
West Midlands Police said it had been told of the plans and officers visited the pub where they found customers following guidelines.
They added pub staff were reminded of their responsibilities over social distancing when a queue formed outside.
Elsewhere, PureGym at Coventry Skydome reported more than 50 members used its gym in the opening 30 minutes of Monday.
And in Warwick, Kelly Boad, owner of the Hair & Beauty Gallery, opened her salon at midnight for a symbolic "first cut" of 2021.
"I thought it would be nice to do a cut as soon as we possibly could and it wasn't hard to find someone who wanted their hair doing after so long," she said.