Four men arrested in relation to the explosion have now been released from custody following interview, Greater Manchester Police said.

Three men, aged 29, 26 and 21, had been arrested under terrorism laws at the Sutcliffe Street address, which is about a mile from the hospital – and a fourth man, aged 20, was detained in the Kensington area of Liverpool.

Assistant Chief Constable Russ Jackson, said: “Following interviews with the arrested men, we are satisfied with the accounts they have provided and they have been released from police custody.

“The investigation continues to move at a fast pace with investigative teams working throughout the night.

“We have made significant progress since Sunday morning and have a much greater understanding of the component parts of the device, how they were obtained and how the parts are likely to have been assembled.”

He added that police had also recovered important evidence from the address at Rutland Avenue which is becoming “central” to the investigation.