A three-match ban is the only appropriate response to Chelsea striker Didier Drogba throwing a coin at supporters on Wednesday night, believes Gordon Taylor, chief executive of the Professional Footballers' Association.

Drogba is under fire after throwing a coin back into the crowd while celebrating his 27th-minute goal against Burnley in the Carling Cup fourth-round tie at Stamford Bridge.

The FA and Metropolitan Police are investigating the incident. Drogba received a yellow card from referee Keith Stroud but it is understood that was for a one-fingered' gesture to the visiting fans.

Chelsea were dumped out of the competition 5-4 on penalties and while the Ivory Coast striker issued a post-match apology for his behaviour, it may not save him from further action.

A Metropolitan Police spokesman said: "I can confirm we are investigating the incident. An inquiry is being conducted by the Football Unit at Fulham police station. No-one has been arrested."

An FA spokesman added: "We are investigating. That's all I can say until we have had a chance to look into it further."

In 2002, Liverpool defender Jamie Carragher was red- carded for throwing a coin back into the crowd. He received a mandatory three-match ban but the FA did not punish him further and the police took no action.

Taylor believes the precedent for Drogba's misdemeanour is already there, and that a similar punishment should be expected.

"It's there for all to see, he's done something that's against the rules required of players, and a similar situation resulted in a three-match ban for Jamie Carragher," he said. "So it would be very difficult to avoid an accusation that they the FA are inconsistent if they don't follow that line."

"In fairness to the lad, he knows he's done wrong, he apologised immediately after the game, but this happened in the heat of the moment and there will be consequences."

Burnley goalkeeper Brian Jensen meanwhile declared his penalty shoot-out heroics constituted the biggest achievement of his career.

Jensen, nicknamed the The Beast' by his team-mates because of his size, earned Owen Coyle's side a place in the quarter-finals thanks to shoot-out saves from Wayne Bridge and John Mikel Obi.

"This is definitely the biggest achievement in my career," said Jensen. "Chelsea had lost one of 86 games at home and yet we came here and turned them over, which shows that anything can happen in football.

"It still hasn't sunk in yet, but I haven't lost a penalty shoot-out with Burnley and I was determined to keep it that way."

Chelsea coach Luiz Felipe Scolari is concerned at the effect on his player of three recent defeats, against Liverpool, Roma and now Burnley.

"Every time we lose it's a problem for us. We need to try again with the confidence for the players," he said.