Oleg Deripaska’s UC Rusal has pledged 25 per cent stakes in its main aluminium subsidiaries to the Russian state as an additional condition to a $4.5bn government bail-out loan, the head of the state-owned bank VEB has revealed.

The disclosure of the pledges on the $4.5bn loan Rusal received last autumn from VEB has provided further evidence of the extent of Moscow’s grip on Mr Deripaska’s metals empire as he battles to keep it afloat and restructure nearly $17bn in loans to foreign and Russian banks.