No. I use London & Country who don't and I find them very, very helpful and efficient. Mortgage brokers that don't charge a fee do rely on commission from the mortgage provider though so, if a lender doesn't offer that, they don't include them in their recommendations.
We used John Charcol and they are very good. Very highly-rated! You pay £250 fee (they get the bulk from commission from lender). I imagine the £250 is to put people just talking to them 'for fun'! And they don't bill you the £250 till you complete. To be honest, I think it's worth every penny. They were very exhaustive in their search and when we went back to them with some better deals we found, they explained why we couldn't get them etc so we felt we got the best deal through them.
I used to work for a mortgage broker. If the broker does not charge you directly then they will get a commission from the lender. This commission should be declared to you on the Key Facts statement and it should not cloud the broker's decision when making a recommendation to you.