A crooked Post Office manager – who used to work in Forest Gate – stole more than �18,000 by repeatedly issuing fake cash bonds to herself.

Jahira Begum, 24, immediately cancelled the postal orders to take advantage of the short delay before the Post Office computer system updated itself to cash the orders before they became void.

A jury at Snaresbrook Crown Court unanimously convicted her of theft.

Begum was remanded for sentence until Friday so probation reports can be compiled.

Alexandra Ward, prosecuting, said Begum started work as counter staff for the Post Office in Forest Gate in 2005.

She become the manager of the Porters Avenue branch in Dagenham in 2009 and spent most of the time running the small branch on her own.

“It was at that point that the Crown say she began to steal money from the post office system,” she said.

She would issue a postal order to a fictitious customer, then cancel it, and cash it.

It would take several minutes for the computer suystem to update and recognise that the postal order had been cancelled.

During these “windows of opportunity” Begum would cash the bond, which she placed in the till as a receipt, without marking it to indicate it had been cancelled, the court was told.

In this way, Begum issued herself 74 postal orders over eight months worth a total of �18,450.

Begum, from Dagenham, denied one count of theft between May 14, 2009 and January 29, 2010.

She claimed that someone else at the Post Office must have been to blame for the missing cash.