There are ATC regulations into LHR due to weather at present. The first INDU cancellation is BA710 to ZRH.
BA456 MAD is due to a lack of aircraft serviceability. TECY.
the same can be said for BA638 ATH, BA428 AMS and BA1382 MAN, BA 696 VIE, BA 342 NCE, BA 295 ORD, BA 434 AMS, BA 780 ARN, BA 852 PRG, BA450 PMI, BA476 BCN, BA 1452 EDI, BA 718 ZRH, BA1314 ABZ, BA 1336 NCL and BA 183 JFK.
So not everything is due to HAL staff striking.
BA 412 to AGP is a lack of crew FCRY as is BA 283 LAX, BA 207 MIA.

Anything else at present is either industrial action in France if a French dest, or security industrial action at LHR, with a couple of previously cancelled flights posted some time ago.