The firm secured the project through negotiated tender at a price of £110.6m, after no other competitive bids were submitted in an open re-tender for the historic building upgrade.

The initial contest to restore Parliament’s tallest building got underway in March last year but had to be called off because of a procurement blunder.

Originally Sir Robert McAlpine, which previously completed similar work to the Elizabeth Tower, Lendlease and BAM were understood to have shown interest in the restoration. But the firms appear to have decided not to take part in the rivised tender, leaving Wates to negotiate the job.

Significant repairs were last undertaken to the 99m tall Victoria Tower in the early 1990s. The building fabric has deteriorated in the intervening period with repairs now needed to the full external envelope.

The complex project will involve shrouding the 160-year-old tower in scaffolding, first to restore the crumbling masonry.

The project’s scaffolding will then also be used to complete conservation works to the window glazing, cast iron roof, rainwater drainage system and flagpole. This will save money by eliminating the need for future scaffolds to carry out these works.

Main work is now expected to start shortly and is expected to take six years to complete.