British outsourcer Mitie said on Tuesday it was confident of its annual outlook as clients reopen their offices and first-quarter revenue more than doubled thanks to COVID-19 contracts and its Interserve acquisition.

Shares in the company, which provides engineering, security and cleaning services, rose 5% after reporting a 104% jump in revenue including those from its joint ventures to 930 million pounds ($1.28 billion) for the quarter ended June 30.

The London-based company has been providing security services in virus quarantine hotels and helping the government roll out COVID-19 testing sites across Britain. Revenue from the contracts came in at 110 million pounds in the quarter.

Britain on Monday expanded a programme of daily COVID-19 tests to reduce a wave of staff absences created by a high number of new cases. Earlier this month, the country lifted most of its pandemic restrictions. 

"We maintain our forecasts (for Mitie) for now but believe there is upside potential depending on how Covid-related work unfolds over the year," Peel Hunt analyst Christopher Bamberry said.

Although its first quarter was mainly boosted by work related to COVID-19, Mitie said it was confident of its full-year performance as the economy gradually recovers from the pandemic, and as it had recently won "high-quality" contracts.

The company, whose customers include IKEA, Vodafone and Bank of England, booked new contracts and renewals of up to 1.4 billion pounds in the quarter.

Mitie said its technical services division, which provides building maintenance and engineering services, may not fully recover to pre-pandemic levels this fiscal year as major customers included pandemic-hit airports and office-based businesses.

Rival Serco last month forecast a 50% jump in first-half profit but warned that revenue from COVID-19 services may ease in the second half. 

($1 = 0.7255 pounds)

(Reporting by Yadarisa Shabong in Bengaluru; Editing by Ramakrishnan M., Shounak Dasgupta and David Evans) ((Yadarisa.Shabong@thomsonreuters.com; Twitter: https://twitter.com/Yadarisa; +919742735150))