The consultancy, led by MD Peter Bingle, has been briefed to smooth the passage of the bill amid concern from some members of the GLA – which is advised by Connect Public Affairs.
The bill proposes to increase the Mayor’s strategic powers in areas including housing, climate change, planning, waste, health and culture.
Launching the bill in November, housing minister Yvette Cooper claimed it would be beneficial for Livingstone and the assembly, which holds the Mayor to account. But some members have voiced concerns that its role could be weakened.
A spokeswoman for the Mayor confirmed: ‘The Mayor of London has appointed Bell Pottinger to support his work on the recently published Greater London Authority Bill.
She added: ‘The Mayor will engage constructively during the passage of this bill to help ensure the successful adoption of the proposed new measures, in particular the important new powers relating to housing and planning.’
Connect Public Affairs, meanwhile, was brought on board by the assembly following a competitive pitch.
Agency director Andy Sawford said: ‘Our brief is to assist the assembly to press the case for an improved balance of power between the Mayor and the assembly.’