Bernie Ecclestone's dream of adding Thailand to the list of new stop on the F1 schedule have taken a potentially fatal blow after a new ruling was passed to protect Bangkok's historic monuments from the effect of motorsport.

The race appeared to have taken a step closer to reality in April, with local newspapers reporting that the Sports Authority of Thailand has signed off on a 3.725-mile circuit that would take the cars right through the heart of the capital city, but the objections of environmental protestors now seem to have gained the upper hand.

The start/finish straight had been earmarked for the Royal Thai Naval Dockyard on the Chao Phraya river near the Rama VIII Bridge, before the circuit snaked past such well-known landmarks as the Khao San Road, Grand Palace, Ratchadamnoen Avenue, the Democracy Monument, the Giant Swing of Wat Suthat, Wat Arun and the Navy Club, before following Phra Sumen back to the start/finish line.

Sports authority representatives claimed that 'only a small group of residents would be affected by the proposed route', but the layout's proximity to some of the country's most historic sites sparked concern amongst environmental groups, which claimed that pollution and vibration from 22 F1 cars would be detrimental to the delicate condition of some of the buildings.

Despite the race not being due to debut until 2015, city planners have already taken action, instigating a ban on all 'car racing' within Bangkok's historic quarter, but insisting that restrictions had been under consideration for some time, and not as a knee-jerk reaction to the idea of bringing F1 to the capital.

"The law came into effect on 16 May prohibiting car racing in inner Bangkok because that area is a conservation for culture and arts," director general Kriangphon Pattanarat confirmed to the AFP news agency.

The department for sport and tourism confirmed that the law was now in place, but indicated that it might still be possible to bring F1 to Thailand, even if it could not run a race in Bangkok, with the resort of Phuket amongst suggested alternatives.

"I was told yesterday about the new city planning law," minister Somsak Phurisisak admitted, "Whatever is illegal we will not do."