(Recasts lead, adds BP denial, background, updates shares)

By Tom Bergin

LONDON, Jan 7 (Reuters) - Shares in Britain's BP Plc (BP.L: Quote, Profile, Research) fell 4 percent on Wednesday as the oil major was, yet again, dogged by rumours it told analysts earnings would be lower than expected.

Three dealers reported rumours that BP had guided analysts to lower their fourth-quarter earnings forecasts and one analyst saidBP had started to contact analysts on Tuesday, to discuss their forecasts.

BP spokeswoman Sheila Williams denied the rumours.

"We do not give guidance on our results," she said.

Financial market rules in Europe and the U.S. forbid companies from divulging market-sensitive information, such as guidance on profits, to selected audiences.

Shortly after the end of each quarter, BP, like many other companies, calls analysts to ask their predictions for quarterly earnings, from which the company then compiles an average forecast.

BP has said in the past that it sometimes highlights positive or negative aspects to the quarter, which have been made public but which it feels analysts may have overlooked.