LONDON (Reuters) – Green groups have formed a coalition against three high-profile London 2012 sponsors, the latest in a wave of protests that have heightened fears that demonstrators are ramping up their campaigns in the run-up to the Games in nearly 100 days’ time.

The coalition, which launched the campaign “Greenwash Gold 2102″ on Monday, argues that Dow Chemical, oil company BP and mining giant Rio Tinto should not be involved in the Olympics because of their environmental records.

The campaign, which includes activist groups the Bhopal Medical Appeal and UK Tar Sands Network, is one of a collection of protests ranging from local communities fighting construction of venues in their neighbourhood to trade unions complaining about work conditions.

Protests have been peaceful, but police and Olympic chiefs are aware the Games, and torch relay, could be a magnet for demonstrators keen to publicise their message at a time when the world’s attention will be on London.

Police last month warned that attention-seekers rather than the violent protesters who marred the torch relay four years ago will pose the biggest threat.

Earlier this month, a lone protester disrupted the traditional university boat race between Oxford and Cambridge, forcing a restart.

Authorities have so far taken a softly, softly approach, with the aim of deterring copycat behaviour, saying protesters have the right to demonstrate peacefully.

But they warn they will clamp down on anyone attempting to disrupt events.

London Olympic organisers (LOCOG) said it had planned for any disturbances, adding it was “confident that any protests will be handled in a sensible and appropriate way.”