Greenpeace stepped up its UK campaign against the import of wood from ‘ancient’ rainforests this week, with activists boarding a container ship carrying African timber to London.

Five people chained themselves to the stern door of the Roxane Delmas in the Thames estuary to stop unloading of timber from Cameroon.

The action follows last week’s invasion of the cabinet office, Whitehall, when 40 Greenpeace members declared it an ‘ancient forest crimes scene’. They claim African sapele used for doors and windows in refurbishment of the building was logged in rainforests.

Meanwhile, prime minister Tony Blair has told the House of Commons that the protest was ‘misconceived’.

He said: ‘My understanding is that the timber being used is indeed certfied as sustainable and therefore the campaign by Greenpeace is misconceived.’

The precise source of the wood for the Cabinet Office project is still unclear, with Greenpeace saying African sapele comes mainly from Cameroon where the Forest Stewardship Council (UK) says it is not aware of any independent certification schemes operating .

  Cabinet office contractor Balfour Beatty has commissioned an independent review of the project’s timber sourcing and certification.