They were allowed inside even though they didn't have any markings or badges on their clothing.
They asked the woman and her daughter, who was present at the time, to go into the kitchen and fill up saucepans with water.
But when the women started to question what was going on and asked the men to leave. One of the suspects was seen to go into another room in the flat.
The women discovered that £300 cash had been taken from a bedroom. The incident happened at Woodville House, Brunswick Road, Sutton, on Saturday, 21 November between 15:30-15:45hrs.
If you have any information to help police enquiries, contact Sutton Police station on 101. Alternatively, contact Crimestoppers anonymously on 0800 555 111.