A shopper has described how she confronted two angry thieves and has warned others to be on their guard.
Toni Cox, 55, of Highams Park, was shopping at the 99p Store in Old Church Road, Chingford, on Friday when she noticed a man staring at her.
As she picked up a bag of cat food, she was then pushed by a woman.
The man then took the trolley into a different aisle and took her purse.
Ms Cox said: "I chased them out of the store and confronted them.
“They were shouting at me and swearing at me telling me I was mad. The man said ‘I will find you and kick your head in’.
"He looked very menacing but I wasn’t going to allow someone to steal my purse especially as it has a picture of my mum who has passed away."
A member of staff tried to diffuse the situation and brought the two thieves back into the store.
They continued to protest their innocence, but CCTV pictures showed the man sliding the purse back into the trolley as he hurled abuse at Ms Cox.
The store manager, who wished to remain anonymous, said: "The man and woman tried to prove to the lady they hadn’t stolen anything but CCTV shows them diving inside her trolley after they pushed her.
"The lady was very distraught and when I mentioned calling the police, the man became quite violent and pushed the assistant manager."
The thieves then ran from the store and remain at large as police did not arrive at the scene until 40 minutes later.
Mrs Cox has warned the public to be vigilant, fearing they may strike again.
She said: "Just be on your watch as this was a scam to take my belongings. I'm particularly worried about the elderly community as they are much more vulnerable and cannot defend themselves as easily."
The man is described as black, 5ft 9ins, of very slim build and wearing a grey overcoat.
The woman is described as black, 5ft 5ins, of medium build and wearing a thick black and white head band.
Police were called to the scene at 2pm and are investigating the matter.
Anyone who witnessed this incident or can identify the suspects should contact Detective Sergeant Vince Fedder of Waltham Forest Police by dialling 101 or call Crimestoppers anonymously on 0800 555 111.