A teenager faces jail for plotting a bomb attack, possibly targeting an Elton John concert in Hyde Park on the anniversary of the 9/11 attacks.

Haroon Syed, 19, from Hounslow, west London, pleaded guilty after a last-ditch attempt to get his case thrown out failed.

The Old Bailey heard how Syed tried to get weapons online, including a bomb vest or explosives, and trawled the web to find a busy area in the capital such as Oxford Circus to launch an attack.

Syed was caught chatting online with officers from the British Security Service who posed as a fellow extremist who could help him source the weapons.

Judge Michael Topolski QC said Syed faced a "discretionary life sentence".

At an earlier hearing, the court heard how key evidence was gathered from Syed's communications with the fake contact Abu Yusuf via mobile phone and social media.

Syed asked for "gear" for his "opp" and when asked to give details, he said he needed a machine gun and an explosive vest "so after some damage with machine gun do martyrdom ... that's what I'm planning to do."

When Abu Yusuf said it would be costly, the defendant told him he was "broke" but pressed on, saying: "You have to find out the price for the machine gun, any gun."

An officer pretended to be Abu Yusuf when they did finally get together at a Costa Coffee in Slough and their conversation was taped.

Throughout August, the discussions continued about making or getting a bomb and acquiring a gun, even though Syed confessed he had never used one before.

On August 30, Syed stressed that he needed a "portable" device, saying: "I might put the bomb in the train and then I'm going to jump out so the bomb explodes on the train ... So ask the brother if he can make that type of bomb with button."

Meanwhile, he researched targets and they arranged to pick up the bomb in exchange for £150 the following week.

Syed asked Abu Yusuf to make sure there were lots of nails in it and added: "I was thinking of Oxford Street ... If I go to prison, I go to prison. If I die, I die, you understand."

He searched the internet for IS, past terrorist attacks, and potential locations which included an Elton John concert in Hyde Park on September 11 last year.