Unfortunately, AirAsia no longer operate flights from the UK and do not have a UK contact number. However, if you are flying with AirAsia whilst on holiday in Asia, for example, you can call one of their national call centres listed on their website.
See this page on the AirAsia website for the full set of options of how to contact them: http://www.airasia.com/ask/template.do?id=29
AirAsia is one of Malaysia’s most popular budget airlines. The airline fly its passengers to 100 destinations in 20 countries, from its main hub in Kuala Lumpur International Airport.
The airline has a number of subsidiaries which operate across Asia in countries such as Thailand, Indonesia, Japan and the Philippines. Whilst AirAsia focus mainly on short-haul flights within Asia, its affiliate AirAsia X take many long-haul passengers to areas such as Australia and the Middle East.