Is it illegal to burn the English flag?

A few weeks ago an englishman settled in our little Welsh village and put an English flag on a pole on top of his house. We weren't to happy with this display of colonialism and decided to peacefully protest by burning his flag. However the flag was quite high and none of us had a ladder so for health and safety reasons we thought it would be safer just to burn his house down.

Satisfied the offending flag no longer tarnished our peaceful village the local retired to their homes. However the council has hit us with a £10 fine for burning in a smoke free zone. Is this fair or are they just weaponizing the law against us?
Is it illegal to burn the English flag?
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