Amazon shoppers are being offered the chance to buy bomb-making components while innocently buying other items, a Channel 4 investigation has revealed.

The retail giant uses an algorithm that suggests buying chemical ingredients, that while harmless on their own, can be combined to make explosives, incendiary devices and pyrotechnics.

Channel 4 investigators were able to create an Amazon shopping basket of up to 45kg of ingredients needed to create explosive black powder- the law only allows a person to create 100g of the substance for private use.

Channel 4 News revealed recipes for explosive black powder and thermite are grouped together under the “Frequently Bought Together” heading during searches for other common chemicals, while steel ball bearings, often used as bomb shrapnel, are also recommended in the “Customers Also Bought” tab.

The news service demonstrated ignition systems and remote detonators were also readily available, and were frequently offered as part of the “Customers Also Bought” suggestions.

Other items included push-button switches, igniter cord, battery connectors and cables - all of which can be used in the construction of bombs.

While many of the ingredients, including one commonly used for food production, are not illegal to buy or sell in the UK, investigators said there had been successful prosecutions of people who bought multiple chemicals and electronic components needed to make bombs.

The revelation came three days after 30 commuters were injured when an explosive device was detonated on a London Underground train at Parsons Green.