Three men were arrested in dawn raids this morning, taking to four the number being held over allegations of terrorism fundraising.
It follows the arrest on Thursday of a 30-year-old British Airways employee in Newcastle. A second BA staff member was among the group arrested this morning.
The three men, aged 31, 32 and 43, were seized by police at 5am today in Slough.
The men are now being questioned about a plot to fund a terrorist attack.
Police refused to clarify what positions the two BA employees had within the airline. Sources said the latest arrests were ‘significant’.
A spokesman for British Airways said: ‘An employee was arrested in Slough today. We take all matters relating to security extremely seriously and as a responsible company always fully cooperate with the police.
‘As with any issue relating to a police investigation it would be inappropriate to comment further.’