MoD staff are banned from taking unencrypted laptops out of offices
The Ministry of Defence says a laptop has been stolen from a member of the military as he was eating in McDonalds.
The computer was taken from under the Army captain's chair, near the MoD's Whitehall headquarters on 1 April, according to the Sun newspaper.
The MoD said the data on the laptop was not sensitive, and was fully encrypted.
It comes after a laptop holding details of 600,000 people who applied to join the armed forces was stolen from a car in Edgbaston, Birmingham, in January.
A Ministry of Defence spokesman said that police were investigating the theft.
It comes after the government tightened the rules on employees taking computers out of work.
Whitehall staff are now banned from taking unencrypted laptops or drives containing personal data outside secured office premises.