SHEFFIELD TERROR PLOT: The latest developments

Officers have started to arrive at the Fatima community centre and mosque in Brunswick Road, Burngreave, to continue the search operation which started yesterday as part of a pre-planned counter terrorism operation

Here is what we know so far:

- Four men, aged 22, 31, 36 and 41 were arrested at their home addresses in Sheffield and Chesterfield yesterday on suspicion of terror offences. They remain in police custody this morning.

- The men were arrested on suspicion of being concerned in the commission, preparation or instigation of acts of terrorism under section 41 of the Terrorism Act 2000 and were taken to a police station in West Yorkshire, where they remain today.

- The men aged 22, 31 and 36 were arrested in Chesterfield and the 41-year-old man was arrested in Chesterfield on a series of dawn raids.

- Officers raided three homes in Sheffield - one in Verdon Street, Burngreave; another in Shirebrook Road, Meersbrook and a one in Stocksbridge. They also raided the Fatima Community Centre and mosque in Brunswick Road, Burngreave.

- The raid in Chesterfield took place in a flat above the Mermaid Traditional Fish Bar in Sheffield Road.

- Army bomb disposal units were deployed to the mosque and Chesterfield flat yesterday as part of the operation.

- In Chesterfield, homes were evacuated around the flat and children at nearby Cavendish Junior School were kept inside as a precaution.

- The raids were carried out by the North East Counter Terrorism Unit said were described as 'intelligence led and pre-planned' as part of an ongoing investigation involving M15.

- The raids were carried out as part of a plan to thwart a suspected Islamist terror plot.

- Additional armed police patrols will be carried out in the wake of the raids.

- South Yorkshire Police said the force has a 'commitment to find and tackle those that want to cause harm'.

- In addition to five attacks in London and Manchester, Home Secretary Amber Rudd revealed earlier this month that security agencies had foiled nine plots since March. Counter-terror teams are running around 500 live investigations.