Police must decide by tonight whether to continue questioning a man held in connection with a suspected terror plot.

Officers arrested the man, believed to be a 27-year-old teacher of Pakistani descent, in Maiden Lane, Crawley, on Thursday evening.

His custody time limit is due to expire this evening and detectives must either charge or release him, or apply to hold him longer under the Terrorism Act.

Eight other men were arrested in connection with a suspected al Qaida bomb plot following a series of police raids on properties in London and the South-East on Tuesday.

They are all being held at the high-security Paddington Green police station in London, where officers have been granted leave to hold them until tomorrow.

Under anti-terrorism laws, police can apply for extensions to detain suspects for questioning for up to 14 days without charge.

The first eight arrested include Omar Khyam, 22, his brother Shujah Khyam, 19, and their cousin Ahmed Khan, 17, all from the Langley Green area of Crawley.

Two other suspects, Jawad Akbar and Waheed Mahoud, are also believed to be from Crawley.

The remaining three men arrested have been named as Anthony Garcia, also known as Rahman Adam, Azhar Shazad Khan and Nabeel Hussain.

The eight British men arrested are all of Pakistani origin.

All the men are being quizzed by officers from the Metropolitan Police anti-terrorist branch in west London.

More than 700 police officers were involved in last week's arrests, which came as half a tonne of ammonium nitrate fertiliser was seized from a west London self-storage unit.

Police said the material was capable of creating a bomb similar to the one used in the 2002 terror attack on Bali.

In Canada, police confirmed a man held on terrorism charges had been linked to the arrests in Britain.

Canadian software engineer Mohammad Momin Khawaja, 24, appeared in court accused of being involved in terrorist-related activity since November 2003 in Ottawa and at or near the City of London, the Royal Canadian Mounted Police (RCMP) said.

Khawaja was the first person to be charged under Canada's Anti-Terrorism Act, which came into effect in December 2001.

He made a brief appearance via video link before the Ottawa court which set a bail date for Wednesday.

RCMP officials declined to provide further details on the alleged connection.

A statement on its web site said: "While we realise that confirming this fact will raise many questions, we cannot elaborate on the details of the connection due to the ongoing criminal investigation."

Police have refused to discuss reports that almost three tonnes of ammonium nitrate fertiliser is unaccounted for after being stolen from a Welsh farm.

Gwent Police refused to confirm whether six 1,000lb sacks were reported stolen from a barn near Abergavenny, south Wales, on November 24.

Scotland Yard's elite anti-terror unit is investigating a possible link between the theft and the seizure of the same type of fertiliser during last week's raids.