Freshfields Bruckhaus Deringer is advising the UK government on the sale of its 40% stake in high-speed train operator Eurostar.

HM Treasury has appointed the magic circle firm as its lead legal adviser, with City corporate partners Simon Marchant and Stephen Hewes heading up the team. UBS is acting as financial adviser.

Chancellor George Osborne has invited initial bids for the stake, which is reportedly worth £300m, by the end of October. HM Treasury is aiming to reach a definitive agreement in the first quarter of 2015, subject to gaining value for money for taxpayers.

French state train company SNCF holds a majority 55% stake in Eurostar, while Belgium's SNCB owns 5%.

Linklaters is advising SNCB with a team led by Brussels-based capital markets partner Charles-Antoine Leunen. SNCF is instructing a team from French corporate boutique Lacourte Raquin Tatar, led by partner Serge Tatar.

The government outlined intentions to sell its share in Eurostar last December as part of a bid to offload £20bn of corporate and financial assets by 2020.

The sale was previously handled by the Department for Transport (DfT), which handed over control of the process to HM Treasury in June.

Earlier this year DfT invited firms to pitch for an advisory role on the sale in a procurement process overseen by general counsel and former Burges Salmon partner Nick Olley.

Firms recently advising the Treasury on other mandates include Allen & Overy, which last year represented the government body on the launch of its £12bn Help to Buy scheme.