* Briton arrested at a London airport
* Suspected wanted over attack on Deutsche Telekom routers
* Conviction could lead to jail term of up to 10 years (Adds Deutsche Telekom comment, background)
By Harro Ten Wolde
FRANKFURT, Feb 23 (Reuters) - British authorities have arrested a suspect in connection with a cyber attack that infected nearly 1 million routers used to access Deutsche Telekom's internet service, German federal police said on Thursday.
Britain's National Crime Agency detained the 29-year-old Briton at one of London's airports on Wednesday, the police said in a statement.
Deutsche Telekom welcomed the arrest and said it was considering bringing civil charges against the suspect.
The attack on Germany's largest telecom company took place in late November. Internet outages disrupted services to as many as 900,000 people, around 4.5 percent of its fixed-line customers.
It was part of a campaign targeting web-connected devices around the globe, the German government and security researchers said at the time.
The man is suspected of targeting Deutsche Telekom's routers to turn them into remotely controlled "bots" for mounting large-scale attacks that disrupt access to websites and computer systems, the German federal police said.
The police said the man, whom it did not name, tried to offer access to the network on the darknet, a part of the internet that cannot be accessed through normal browsers and is seen as harbouring criminal activity.
Public prosecutors in the German city of Cologne have requested extradition for the man who faces up to 10 years in prison if found guilty. (Reporting by Harro ten Wolde and Peter Maushagen; Editing by Maria Sheahan and Keith Weir)