Ashurst and Allen & Overy have picked up mandates on Transport for London's (TfL) construction of the Silvertown Tunnel in London.

TfL awarded the contract to Riverlinx Consortium – including financial institutions Aberdeen Standard Investments and Macquarie Capital – which will design, build, finance and maintain the £1 billion tunnel that connects the Royal Docks and Greenwich.

The tunnel, which is set to open in 2025, has been controversial, with campaigners claiming that it would affect air quality and congestion in the areas.

Ashurst is advising longstanding client TfL on the transaction with a team led by projects partners Terry van Poortvliet and Jonathan Turner.

In March, van Poortvliet led a team advising TfL on the sale and leaseback of Elizabeth Line (Crossrail) trains to a consortium, in a deal that released about £1 billion of capital to be reinvested into London's transport network, including delivering a fleet of Piccadilly Line trains.

A&O is advising the consortium on the current deal, with the firm's global head of infrastructure David Lee leading for the firm. London partners Mark Walker and Sara Pickersgill also took roles on the deal, alongside Madrid-based partner Charles Poole-Warren.

Ashurst was recently reappointed to TfL's 15-strong legal panel, and earlier this year took a role on TfL's £15 billion Crossrail project.

Last month, Legal Week found that eight firms had shared more than £22 million during the past two years for their work on government rail project HS2, according to the government department's spending data.