Sky News has learnt that Zenobe, which has placed itself in the vanguard of the transition to electric vehicles through its proprietary technology, has begun sounding out investors about the capital-raising.

City sources said on Friday that the primary share sale was likely to raise between £350m and £400m from new and existing shareholders, while a secondary sale of shares would take the total value of shares changing hands to at least £500m.

The scale of the deal, on which bankers at Barclays are advising, underlines Zenobe's ambitions following a period of spectacular growth.

The company has told prospective investors that they will have the opportunity to invest £1bn in its shares during the next four years as it keeps pace with demand from new customers.

Zenobe provides fleet electrification services, making it attractive to so-called ESG investors which have a focus on backing environmentally sustainable businesses.

It boasts a 25% share of the still-nascent UK electric bus sector, and counts National Express and Stagecoach, two of the country's biggest bus service operators, among its customers.

Zenobe also repurposes EV batteries after their initial life, providing power solutions to industries such as film and events.

The UK-based business is already backed by prominent investors such as Infracapital, an arm of M&G, the FTSE-100 asset manager.

Its other shareholders include the Japanese companies Tepco and Jera.

Chaired by Steve Holliday, the former chief executive of National Grid, Zenobe describes itself as an international EV fleet and battery storage specialist.

The company is run by Nicholas Beatty, who also founded two solar energy companies in the UK.

According to one fund which has been contacted about the capital-raising, Zenobe is forecasting that it can achieve earnings before interest, tax, depreciation and amortisation of at least £400m by 2026.

That sort of financial performance would attract a valuation running to many billions of pounds.

Zenobe declined to comment.