From the BA website:
BA cabin crew strike 2010 - Chartered aircraft operated flights
We are chartering a number of aircraft from a range of UK and European based airlines to assist with our shorthaul (UK and European) operations to and from London Heathrow.
The following airlines are being chartered for flights operating between 20 and 22 March 2010:
Air Finland
Arkefly
Astraeus
EuroAtlantic Airways
Jet2
Titan Airways
Transavia
Viking Airlines
These charter companies employ the pilots and cabin crew working on these aircraft, which will be operated on behalf of British Airways.
We have worked successfully with several of these airlines in the past. All of these airlines have to comply with the strict safety and operational standards laid down by Civil Aviation Authority (CAA) and European Aviation Safety Agency (EASA) and any requirements specified by British Airways.
Flights operated by chartered aircraft will use the existing BA flight numbers.
Will the charter aircraft be using the 'speedbird' callsign or using there own company callsign?