European markets are under pressure amid fears the current unrest in Egypt could cause instability across the oil-rich Middle East.
The FTSE 100 Index fell 47.2 points to 5834.7, with travel-based stocks such as InterContinental Hotels, TUI Travel and British Airways owner International Consolidated Airlines Group among the leading fallers.
The price of Brent crude remained near 100 US dollars a barrel after spiking on Friday, while the US dollar strengthened as traders sought refuge in traditional safe haven currencies.
Heavyweight banks such as Barclays were shaken by the uncertainty, with the UK heavyweight down 8p at 290.2p, a drop of nearly 3%.
With Thomson holidays owner TUI Travel cancelling flights to the Egyptian city of Luxor, shares in the FTSE 100 Index company dropped 6.9p to 252.9p.
Newly-merged BA and Iberia firm IAG dropped 7.1p to 252.9p, while InterContinental Hotels slipped 32p to 1297p.
Greene King topped the FTSE 250 Index risers board after it became the latest pubs group to reveal resilient trading over the festive period.
The group, which saw shares rise 2% or 9.3p to 457.8p, forecast more profitable growth over the rest of the financial year and announced the £55.8 million acquisition of restaurant business Cloverleaf.