Closure of the deal is expected during the second quarter of this year. However, the sale is conditional on regulatory approval, and Eurostar's other two shareholders, French National Railways (SNCF) which has a 55% stake and Belgian National Railways (SNCB) with the remaining 5%, not exercising their option to purchase the government's 40% stake for a 15% premium on the £585.1m sale price.

When the British government launched the competition to sell its stake in Eurostar in October last year its holding was valued at £325m. UBS acted as an advisor to the government on the sale.

Patina Rail comprises Caisse de dépôt et placement du Québec (CDPQ), a Canadian institutional investor which manages funds for 33 pension and insurance plans and which holds around $C 226bn ($US 180.5bn) in net assets, and Hermes Infrastructure, Britain, which manages funds worth about £3bn. CDPQ will have a 30% stake in Eurostar and Hermes 10%.

The sale is part of the British government's controversial plan to sell £20bn in assets between 2014 and 2020 to help reduce Britain's national debt, which stands at around £1432bn, or 75% of GDP.

Eurostar operates high-speed services primarily between London, Paris and Brussels. In 2014, it recorded a 3% increase in traffic to 10.4 million passengers and a 20% jump in operating profit to £55m.