Mr Gummer last week gave his go-ahead for offices abutting the Thames at Vauxhall and blocking the riverside path - just a fortnight after he promised to get tough with developers who built unsympathetically along the waterfront. His move runs directly counter to the Thames Strategy, which he commissioned and which includes a commitment to prevent encroachment on to the river's foreshore.
Until now, walkers could stroll all the way along the south bank of the Thames from Tower Bridge to Battersea Park. While several buildings block the path on the north bank, the south offers an inspiring trail past the remains of the Dickensian Clink and Marshalsea prisons, alongside the new Globe Theatre, and on to the Festival Hall. It is then possible to continue through Jubilee Gardens, past the Houses of Parliament and Big Ben on the other side of the Thames, and on to Battersea Park.
However, Mr Gummer has approved plans for 100,000sq m of offices next to Vauxhall Bridge. The buildings, designed by Terry Farrell, will come right down to the bank.
Objectors to the proposals - who included the National Rivers Authority, the London Wildlife Trust, Lambeth Council, English Heritage and the London Rivers Association - have fought a long battle against the plans for the development.
The Thames Strategy was greeted enthusiastically by those who had campaigned for the river's banks to be open to the public - and the biggest fillip to their cause had been Government backing in 1989 for the Countryside Commission's proposed trail, the Thames Path, following the line of the river along previously restricted or private towpaths from its source in Gloucestershire to the Thames Barrier in Woolwich.
Environmentalists fear the Vauxhall site could set a precedent for development of other river sites.