People who want to build homemade explosive devices can easily buy bomb ingredients on Amazon, where they can find the necessary chemical combinations through "suggested items", an investigation has found.

The online retail giant's algorithm groups together items that are "frequently bought together" and suggests them to buyers. Ingredients that are innocuous on their own, can be bought together to produce incendiary devices.

These items include ingredients for chemical explosives such as black powder and thermite .

Such ingredients are grouped together under a "Frequently bought together" and "Customers who bought this item also bought" sections, Channel 4 discovered.

Igniter cord and steel ball bearings, the latter often used as shrapnel in explosive devices to maximise the number of casualties during an attack, can also be purchased.

People who conducted the investigation claimed that they were able to create a "shopping basket" on Amazon with up to 45kg of ingredients for black powder. However, under current legislation, people can only produce 100g of black powder for private use without storage.

A spokesperson for Amazon told IBTimes UK: "All products sold on Amazon must adhere to our selling guidelines and we only sell products that comply with UK laws. In light of recent events, we are reviewing our website to ensure that all these products are presented in an appropriate manner.

"We also continue to work closely with police and law enforcement agencies when circumstances arise where we can assist their investigations," the spokesperson continued.

The investigation came days after a botched bomb attack left 30 people injured on a train in west London. Police said the bomb used in the attack – which had been hidden in a white bucket and carried in a Lidl plastic bag – was homemade.

In the aftermath of the attack, images and videos posted on social media showed a flaming white bucket from which wires were protruding. Forensic experts said that the explosion could have been fatal if the device had detonated properly.

Two suspects have been arrested in connection with the terrorist incident. The Isis terror group has claimed responsibility for the attack.