Business travellers will have to place laptops and other electronic items in their checked baggage, the Home Office said today.

The new rules were introduced after the arrest of 21 people this morning in connection with a terror plot to blow up as many as 10 aircraft.

Increased security measures have resulted in huge queues and cancelled flights all over the country.

Under the new restrictions, passengers may only take the following items into the cabin in a, preferably transparent, plastic bag:

British Airways was advising passengers not to travel unless it was essential.

"Any customers who do not need to travel today are advised to stay at home," the company said in a statement.

"Customers who have to travel are advised to check on ba.com where they will be able to find the very latest up-to-the-minute information regarding every British Airways flight."