Watford have issued “a last and final plea to their supporters” after the FA threatened the club with sanctions due to their fans’ use of pyrotechnics.

There have been a number of instances this season where smoke bombs and flares have been let off by Hornets followers at away grounds, most recently at Leeds United.

Watford have previously warned supporters they face the prospect of criminal prosecutions and club bans if they use pyrotechnics.

But last night the Hertfordshire side revealed the FA has warned the Golden Boys the governing body is likely to impose sanctions on the club should their supporters continue to use pyrotechnics at any ground.

Watford’s statement read: “Despite a number of requests to desist, issued here at watfordfc.com and supported via other communication channels, Watford fans once again suffered from the use of pyrotechnics by fellow supporters at Leeds United on Saturday, December 7.

“The club now finds itself in the onerous position of having to issue a last and final plea to its supporters, especially those who frequent away matches, to ask that due notice is heeded of previous warnings.”

In a previous statement, the Hornets added: “The use of pyrotechnics has no place in English football and we would urge all supporters to take positive action in assisting to eradicate this unlawful practice.”

Research conducted with 1,635 Premier League supporters found 87 per cent of fans believe pyrotechnics are dangerous at matches and that 86 per cent were concerned for their safety. The same number thinks flares and smoke bombs are a fire risk and 79 per cent consider them to be a health hazard.

Andrea Brown, the Football League’s head of customer services, has previously said: “There really is no need for anyone to take pyrotechnics to a football match as they put fellow fans at risk of injury. Supporters who do so are acting illegally and risk being banned from professional football and sent to prison.”

Alan Weir, head of medical services at St John Ambulance, added: “We know that St John Ambulance volunteers have treated people for burns and smoke inhalation caused by flares at several football grounds.

“These cases could have led to disfigurement or other serious injuries so we’re advising fans to seek prompt emergency help should they come into contact with a flare to help prevent their injuries from getting worse. Our volunteers are trained and equipped with life-saving skills to help those who need it. We urge fans to stop using flares and think about the safety of those around them.”