Singapore Grand Prix organisers have rubbished suggestions that static electricity from a passing underground train ended Mark Webber's hopes in the inaugural Formula One night race.

The Australian had been on course for a possible podium at the time of his mechanically-induced retirement, and Red Bull Racing later claimed that a sudden electrical surge - which it believed could have been caused by the city-state's Mass Rapid Transit system - had knocked the RB4's electronics out of action.

Although the official reason for Webber's retirement was listed as gearbox failure, team principal Christian Horner this week claimed that the surge, thought to have occurred at turn 13 on the 23-corner layout, had been responsible for the Australian's 'box trying to select two gears at once.

"There is no MRT track beneath Turn 13," an SMRT spokesman told local media, "The nearest MRT tunnel is about 200 metres away, with a depth of about ten metres.

"In addition, train wheels and running rails are made of metal and therefore do not generate static electricity charges during train operations."

Webber had found himself in a higher-than-expected position after Red Bull managed to get him pitted for fuel and tyres almost as soon as Nelson Piquet Jr's accident threatened to bring the safety car out, and both the Australian and team-mate David Coulthard were well up the order on the race's resumption. After Webber retired, however, Coulthard also ran into problems, notably at his second pit-stop, and the team was left to wonder what might have been instead of savouring the Scot's two points for seventh place.