Fans attending the John Smith’s Stadium are being urged to “remain vigilant” to the threat posed by terrorists.

Counter-terror police are warning football clubs and fans to be on their guard although there is no specific intelligence of an increased threat.

The warning follows four UK terrorism attacks this year, including a suicide bombing at the Manchester Arena which killed 22 people and injured 59.

Officials from the John Smith’s Stadium and other grounds have attended police workshops in recent weeks designed to address the potential threats faced by sports grounds.

The workshops, held at Wembley and Old Trafford, were led by Counter-Terrorism Unit officers.

Tim Dale, deputy safety officer at the John Smith’s Stadium, said spectators may notice increased security at Huddersfield Town’s first home game in the Premier League on Sunday.

The general advice is “remain vigilant, be alert but not alarmed,” he said.

Mr Dale, a former West Yorkshire Police officer, pointed out that the current UK threat level is ‘severe’ which means an attack is ‘highly likely’.

In recent weeks security at the John Smith’s Stadium has been reviewed and updated following advice from counter-terrorism officers.

“We are a place where crowds gather and police have advised all crowded places to continually review security,” says Mr Dale.

“People can be confident we are not ignoring the threat. We are doing everything we can do give people a safe and enjoyable experience.”

Although stadium officials have acted on police advice they cannot go into detail other than to say that fans may notice an ‘upping of the search regime’.

“We are asking people not to bring in bulky bags as they will delay the process of getting into the stadium.

“We want people to arrive in good time and not leave it until the last minute. We are not banning bulky bags but are asking people not to bring them.

“The stadium is keen not to say much about the precautions taken as it would give anyone with hostile intentions an advantage,” he added.

The advice follows comments made this month by Supt Dave Roney, the deputy national co-ordinator for the ‘Protect and Prepare’ counter-terror strategy.

He said: “While there is no specific intelligence of an increased threat to football grounds in the UK, we have seen that terrorists are prepared to carry out attacks on this type of target.

“We have been pleased with the response from the football authorities in attending our events and making renewed efforts to do all they can to keep supporters safe.”