Faster, higher, stronger: the Olympic training regime of man who climbed the Shard

The Shard, the European Union's tallest building, under construction in the center of London (AFP)

The image of a hooded man coolly hanging off Europe's tallest building is not easy viewing for those with a fear of heights, but it will be the accompanying claims of the "urban explorers" who took the picture which will cause the biggest headache for London.

This is because members of the group, who released dramatic images from their break-in to the 1,016ft Shard on the internet, have revealed it is just one of a number of high-profile sites they have routinely entered – including the Olympic Stadium.

They have also mocked the security of buildings across the capital with one member, Bradley L Garrett, telling The Independent: "I could do it again".

Members of the London Consolidation Crew who staged the "exploration" of the tower, which is being built above London Bridge station, have now "visited" the Olympic Stadium as well as more than 300 other landmarks including Battersea Power Station, St Paul's Cathedral and Heron Tower.

And last night it emerged that more could be in the pipeline after members of the group said they planned to target further landmark across the UK and Europe in the coming months.

Mr Garrett, a former PhD student, 31 – who posted the Shard photographs on his website Placehacking.co.uk – said the crew had visited the building a number of times. And despite claims from the developers Sellar Property Group that security had been tightened in the past year, it remained highly vulnerable, he claimed. "I could do it again tomorrow if I wanted to," he said.

"To me it is very political. There are a lot of places that you are not allowed to be or go. I am showing people that, if they want to access these places they can," he added.

Images of an apparent walk-in to the Olympic Stadium in 2010 will add to concerns over security at events this summer following the disruption of the Boat Race on Saturday by an anti-elitism campaigner.

Trenton Oldfield's swimming protest led to a warning from the chairman of the British Olympic Association, Lord Moynihan, that there was little London 2012 organisers could do to stop lone demonstrations causing disruption.

Meanwhile, the post describing the action at the Olympic construction site where world leaders and 80,000 spectators will watch the athletics events claimed that electric fences were not switched on. Images show the then still under-construction site photographed from high above the seating areas.

"Given the stadium was still essentially just a core, there was nowhere to hide. We stuck out like sore thumbs," the post said.

A spokesman for Locog, the 2012 organising committee, said: "Security is a lot different to what it was then as the park is in a more advanced state."