The company's shares rose 17% in early trading after Serco said it now expects annual revenue of around 3.9 billion pounds and underlying trading profit in the range of 160 million pounds to 165 million pounds.

A focus on public sector services has sheltered Serco from the impact of the health crisis. Weakness in its transport services was offset by additional work for governments and provision of COVID-19 testing and quarantine facilities.

The company said performance in all regions was better than it expected, and that it was awarded more work related to COVID-19 test and trace services for Britain's National Health Service and immigration services in Australia.

However, the outsourcer stuck to a cautious tone for 2021, and said it expects uncertainties would persist into next year as coronavirus infections are on the rise.

London-listed Serco, which provides services in hospitals, prisons and nuclear facilities in more than 20 countries, previously expected revenue in 2020 to be roughly 3.7 billion pounds and profit between 135 million pounds and 150 million pounds.

(Reporting by Pushkala Aripaka in Bengaluru; Editing by Krishna Chandra Eluri)