If there has been no strike action taken by the 29th of March, and BA are in agreement, then yes the ballot mandate can be extended for 28 days. This would then leave the union in the position of having to either take strike action by the 27th of April or they would require to re-ballot their members for a fresh strike ballot.
So if i understand that right, strike action would have to be taken and finished by April 27th. The union couldnt say announce a 12 day strike starting on April 26th.
And one final point, ive had a quick flick through this thread but was also wondering. Lets say the union announces a series of walkouts will start from Monday March 1st. Would that mean they could only strike for up to the next 28 days, no further action could be taken after the 28th March without a re-ballot.
Just curious to understand how this strike action works.
Cheers