Pigeons in attic -how to get rid?

[peridito]

Friend has bought top floor flat .Lengthy business and it's been unoccupied .

Pigeons in attic - any advice on how to get them out before sealing entry spot?

Will it have to be a professional job ?

My nephew is a pest controller.
With a gun licence.
I imagine it would have to be professionally done

that was my fear...

Our last property had them in the roof of an outbuilding. It's worth finding out where they sit - if they can't sit, they won't come in. We crinkled up foil and got some (safe not harmful) bird deterrent spikes and the pigeons soon went and made their resting place the tree outside instead!