Save the Children International’s income more than doubled last year to around £550m as it takes over more aid work from national charities.

According to the charity's recently published annual report and accounts, international operational work is being transferred from country offices to the international organisation, a UK-registered charity which has 30 members in different countries.

Most of Save the Children’s country offices have now transitioned their international operational work to Save the Children International. The process began in 2011 and ten country offices became part of the international body during 2013. Two transitioned earlier this year with three left before the process is complete.

Income for the year ending December 2013 totalled US$874m (£548m) up from $338m (£212m) the previous year. The majority of its income is voluntary income received directly from its member organisations. The United States contributed the largest amount, $363m (£228m), followed by the UK at $233m (£143m).

Expenditure was $861m (£540m) as the international organisation responded for the first time to a natural disaster by providing aid to the people affected by Typhoon Haiyan in the Philippines.

The report said: “Following two years dominated by transitions, 2013 was the first year that enables the true scale of operations of Save the Children International to be clearly seen.”

The average number of full-time employees was 11,061. One unnamed member of staff earned more than $390,000 (£244,000).