The Sun has apologised to the families of the victims of the Birmingham pub bombings after wrongly suggesting that police resources were diverted at a football match to deal with a group of campaigners who were raising funds to pay for legal fees.

The false claim was made in a report on the Birmingham City v Aston Villa game, in which a fan was arrested and jailed after running on to the pitch to punch one of the players, Jack Grealish.

The paper dedicated multiple pages of coverage to the incident, describing the “toxic atmosphere outside the game” where Birmingham City fans were allegedly baiting Villa fans.

It also said the “police had their hands full with a protest also being at the ground” by Justice For The 21, a campaign for the victims of the 1974 Birmingham pub bombings, which killed 21 people and wounded 220. The newspaper said the campaigners had held “a demonstration that the police eventually restrained”, putting it in the wider context of the authorities losing control over the stewarding of the match.

Justice For The 21 said its members were not demonstrating and did not need to be restrained by police. Instead, they were asking for donations from members of the public towards legal fees to ensure families were represented in the recently reopened inquests into the deaths.

The families say they have been forced to resort to bucket collections outside big events after not receiving sufficient public funds through legal aid to pay for their lawyers, and that they raised thousands of pounds at Sunday’s match.

West Midlands police later confirmed that no protests had taken place outside Birmingham City’s ground on the day of the match.

After supporters of Justice For The 21 complained to the press regulator, Ipso, the newspaper apologised on Wednesday and retracted any suggestion that the campaigners distracted the police.

The Sun said: “We wish to clarify that members of the group were there as fundraisers, not demonstrators, and that there was no suggestion that the group had caused any trouble for police. The Sun has publicised the work of the group over a number of years, which campaigns for the 21 victims of the 1974 Birmingham pub bombing. We apologise if any offence was caused.”