Sales of a survival kit for commuters have rocketed since the bombings in London on 7 July.
The basic commuter kit contains a particle mask to aid breathing
The kit, which fits in a backpack or handbag, contains a particle mask to filter out dust, a torch, whistle, water and antiseptic wipes.
SurvivalBox.co.uk, the Surrey-based company which sells the packs on the internet, said its sales had risen by 150% in the past three weeks.
The business was started by a survivor of the 11 September attacks.
Several thousand more kits have been sold since the bombings in London, according to managing director Simon Johnson.
He said: "People are buying the kits to reassure themselves about travelling on the underground.
"Our customers want to demonstrate that they are not afraid. Having a commuter kit gives them the confidence to go back on the tube."