Revealed: Inside the Leeds bomb factory where 7/7 terrorists plotted

Pans used to boil down the hydrogen peroxide used in the deadly homemade devices sit on the hob in the kitchen, while the bath is filled with containers of chemicals.

The pictures show the chaotic scene that met police when they raided 18 Alexandra Grove, Leeds, five days after the July 7 2005 London bombings.

Officers found two kinds of high explosive, an improvised detonator, respirators and scraps of paper listing equipment needed and the quantities of chemicals to mix to make the bombs.

Hot plates linked to fans used to make the hydrogen peroxide more concentrated were found throughout the two-bedroom ground-floor local authority flat.

Plastic tubs containing a yellow-brown explosive sludge were left open in one of the bedrooms, while the lounge was littered with packaging from items bought for the bombs.

Curtains were taped to the walls to stop prying eyes seeing what was going on inside the flat.

The detonator was made from a lightbulb, wire, aluminium foil and a high explosive called HMTD, the inquest heard.

Dc Richard Reynolds, of the Metropolitan Police's SO15 counter-terrorism command, said: "A lot of these items have an innocent everyday use, but in the context of this particular inquiry are significant."

The respirators were used by the terrorists because the hydrogen peroxide gave off noxious fumes as they boiled it down, killing plants outside one of the flat's windows and blistering the paintwork inside.

Dc Reynolds noted: "The environment that they are working in would have been quite hostile."

The bombers - Mohammed Sidique Khan, 30, Shehzad Tanweer, 22, Jermaine Lindsay, 19, and Hasib Hussain, 18 - made no attempt to disguise their work at the flat, the inquest heard.

The police officer said: "Within the actual premises itself, nothing was actually secreted or hidden."

Gareth Patterson, barrister for four families who lost loved ones in the London bombings, questioned whether neighbours might have picked up on the bleach-like smell of hydrogen peroxide.

Dc Reynolds said: "Potentially there's an unusual smell generating from the open window... I would be inquisitive if I smelt that, and I would go and have a look at it - but that's just me."

The inquest was also shown pictures of smaller bombs found in the Nissan Micra used by three of the bombers to travel from Leeds to Luton station on the morning of the attacks.

These devices, which had nails taped to the outside, could have been thrown at police if the terrorists were caught, the hearing was told.

The main bombs used in the attacks on three Tube trains and a double-decker bus contained about 10kg of explosives made from a mixture of concentrated hydrogen peroxide and pepper and were detonated by a 9-volt battery.

Forensic explosives expert Clifford Todd said using this combination of materials for a bomb was thought to be "entirely unique" both in the UK and worldwide.

He also agreed that the four July 7 terrorists would have needed "guidance and instruction from elsewhere" to be able to make the devices.

Mr Todd said the fact that intact identification belonging to the bombers was found at all four attack sites suggested they made deliberate efforts to ensure it was found.

He suggested they could have placed the ID in separate carrier bags near their rucksacks so it was not obliterated in the blasts.

The coroner, Lady Justice Hallett, noted: "Plainly, no attempt was made to ensure that they couldn't be identified. On the contrary, it looks almost as if they had made attempts to ensure they could be."

The July 7 attacks were the worst single terrorist atrocity on British soil, killing 52 innocent people and injuring more than 700 others.

The inquest at the Royal Courts of Justice in London, which is due to finish in March, was adjourned until tomorrow.