Buying back shares would by extension increase Ferrovials...

Buying back shares would by extension increase Ferrovials shareholding as the total number of shares on offer decreases their % of holding increases.
Example... There are 100 shares on issue. Ferrovial hold 15 at 15%.
BRS buyback 20 shares being 20%.
Ferrovial without doing anything then hold 15 of 80 shares on issue increasing their % holding to 18.75%.
Based on above I would not expect buyback to start in the middle of a takeover.

I do not hold BRS