An investigation has been launched into claims Isis terrorists hacked the personal details of Croydon Council staff.

The names, email addresses and passwords of council workers were reported today to have been leaked online by the extremist group's hacking division.

Data relating to personnel at the Foreign Office, Stockport Council and the American military were also contained on the leaked spreadsheet, according to the Daily Telegraph.

Croydon Council said it had found no evidence of any security breach but was investigating the claims.

However, the Croydon Guardian has seen a document purporting to expose the breached data and found it contains no information relating to Croydon Council or its staff. 

The spreadsheet, posted online by a Twitter account claiming to represent Isis's hacking division, does appear to list names, email addresses, passwords and phone numbers for thousands of US military staff, as well as some Foreign Office personnel and one woman who works for Stockport Council. 

The data is accompanied by the message: "O Crusaders, as you continue your aggression towards the Islamic State and your bombing campaign against the muslims, know that we are in your emails and computer systems, watching and recording your every move, we have your names and addresses, we are in your emails and social media accounts, we are extracting confidential data and passing on your personal information to the soldiers of the khilafah, who soon with the permission of Allah will strike at your necks in your own lands!"

The document does not appear to list any Croydon Council workers, email addresses, password and phone numbers.

Experts have also cast doubt upon claims the data was obtained through hacking. 

Troy Hunt, a prominent computer security writer, said: "The data is almost certainly from multiple locations and very unlikely to be from a single data breach.

"It appears hastily coupled together with inconsistent data structures and duplicate records."

A Croydon Council spokeswoman said: "The council is aware of the allegation and is currently investigating its legitimacy.

"We would however like to reassure people that we have found no evidence of a security breach within council systems."