Sick ISIS supporters celebrate London bucket bomb and claim it was a TRIAL RUN for bigger attack – as they mock ‘weak’ British spooks

ISIS supporters have been celebrating the terror attack on the Tube this morning while chillingly saying it "demonstrated a weakness" in British security.

Sick Telegram messages seen by The Sun reveal terror sympathisers gloating about the device on the London Underground.

One supporter in the group posted that "It reached me today that London know no peace today" accompanied by a heart emoji.

The supporter then adds "It goes like, BOOM! Loud BOOM!" again followed by a heart emoji.

Sharing a screenshot of a TV report of the attack they go on to post a re working of the national anthem saying: "Send him victorious. Happy and glorious. Long to reign over us. God Save the Khalifah."

Others went on to mock Brit spooks branding them "weak" as well as encouraging whoever planted the bomb to "learn from their mistakes".

The jihadi group has not claimed responsibility for the device that was left on a train and went off at Parsons Green station but are "rejoicing" at the news according to SITE Intel Group.

The intelligence organisation tweeted: "As #ISIS supporters celebrate news on #LondonExplosion, one remarked that the incident demonstrates 'weakness' in UK security."

SITE Intel has access to correspondence within the terrorist network.

Cops are desperately hunting a Tube terrorist who injured 22 in a bucket bomb blast at Parsons Green station this morning.

The homemade device connected to a timer sent a "fireball down a carriage" as it detonated with a schoolboy and pregnant woman among those injured in the rush-hour terror explosion.

Mayor of London Sadiq Khan announced "a manhunt is underway" as bomb squads and counter-terror cops swarmed on the scene.

He added: "The person or people responsible for this attack will be caught and will be brought for justice."

Police have revealed that the homemade bomb, likened to pressure cooker devices used in 2013's Boston Marathon attack, did not fully detonate.

The 2013 bombs, which killed three and injured hundreds, were packed with nails and ball-bearings to cause maximum damage and it is not yet clear if today's device had similar projectiles.

Theresa May is being kept informed of developments after the fifth major terror attack on British soil in six months.

The Prime Minister has confirmed she will chair an emergency meeting of Cobra this afternoon, where it is believed she will discuss raising the threat level from severe to critical. .

She tweeted: My thoughts are with those injured at Parsons Green and emergency services who are responding bravely to this terrorist incident."

Today's explosion follows four previous attacks in 2017 which saw five innocent people killed in Westminster in March, 22 killed in the Ariana Grande bombing in Manchester in May, eight killed in the van and knife rampage on London Bridge in June and one man killed when a van rammed into worshippers outside a North London mosque.

Donald Trump has hinted that the attacker may have been known to security services in a string of Tweets posted this morning. Met Police later said the US President's posts were "pure speculation" and "unhelpful".

What we know so far:

• A homemade bucket bomb connected to a timer sent a "fireball" hurtling through an eastbound District Line tube at Parsons Green at around 8.20am
• The Metropolitan Police confirmed they are treating the horror as a terror attack and are hunting the suspect behind the blast
• 22 people have been taken to four hospitals across London including a young boy believed to have suffered serious burns to his legs
• Train services through the area have been halted and a wide cordon put in place after terrified commuters were injured in a "stampede"
• Theresa May will chair an emergency meeting of Cobra today as she said her thoughts are with the victims, while US President Donald Trump has hinted that the attacker may have been known to security services
• Initial reports falsely suggested a knifeman was on the loose and a second bomb was being detonated