There is a SEAGULL in my FLAT!!! HELP!!!!?

Please, help! I live in the city centre of Bath, and it has never been a problem till now, a seagull has flown into my attic! Please help as I am petrified of birds, and though it is only trapped in the attic for now, I am worried as to how it will leave. My husband is on holiday to Spain now (I am on his account) and he normally takes care of these things except this has really never happened before! Should I call an exterminator? Any help much appreciated! x