Taxi firm Addison Lee swung to a loss last year after it was stung by investment and acquisition costs.

The group posted a pre-tax loss of £20.8 million in the year to August 2017, compared to a profit of £10.5 million the year before.

Addison put the fall down to “intense long-term investment”, acquisition integration and reorganisation, which culminated in £18.6 million exceptionals.

However, revenue rose by 31% to £345.8 million in the period, with the firm on track to post over £400 million in sales this year.

Sales were helped by a return to growth in London, which helped drive up UK revenues 11%.

The taxi firm has been looking to keep pace with the astronomical rise of Uber, which has radically shaken up the industry with its ride-hailing smartphone app.

As part of these efforts, Addison has expanded rapidly into the US, snapping up rival Flyte Tyme as well as boosting its global footprint by buying Tristar Worldwide, which has operations in 80 countries.

Boss Andy Boland said: “For Addison Lee Group, 2017 was the year our London business returned decisively to growth and our focus became investing in and building the world’s leading managed ground transportation business.

“We’ve made a strong start to the new financial year, with first quarter revenues up 23% and set to top £400 million for the current financial year.

“At the current rate of growth, we expect to double the size of Addison Lee Group in the next three years.”

The group is also leading a consortium in London to evaluate the impact of new vehicle technology, including the introduction of autonomous vehicles, into the Royal Borough of Greenwich.

With the backing of Government funding from Innovate UK, Addison is partnering with autonomous vehicle technology firms to test inclusion of autonomous vehicles into its operating model.

Addison Lee, which is owned by US private equity firm Carlyle Group, was founded in Battersea in 1975 and has grown to become Europe’s largest private hire car service company, carrying out 10 million journeys per year.