Several police units attended an incident at an Ipswich school after it went into lockdown. 

Officers were called to Ipswich Academy at about 3.10pm on Monday after an email was sent to the school which sent it into lockdown. 

The school's invacuate procedure was triggered and police were called. 

A spokesman for Suffolk police said: "Police received a report of an email being sent Ipswich Academy yesterday afternoon at 3.10pm that prompted the school to initiate a lockdown.

"Several unarmed police units attended to provide reassurance and the invacuation ended at about 3.40pm.

"Enquiries are underway to establish the source of the email.”

A letter sent by headteacher Samuel Fox to parents and guardians reads: "We are writing to inform you that we used our invacuation procedure at the end of the day, leading to a delay in the departure of the students. 

"As you may be aware, all schools are legally required to have practices and procedures in place to respond to various situations of risk.

"Ipswich Academy students have practiced these regularly. 

"The safety of our students is at the heart of all we do so we would like to take the opportunity to thank them for the calm and focused way in which they responded to this unprecedented event."

Ipswich Academy has been approached for a comment.