Broadcast Magazine is reporting that viewers have been contacting Channel 4 to express concern about the broadcaster's "reliance on sick and puerile humour and strong language."

A Comedy Roast (pictured), Channel 4's Comedy Gala and Frankie Boyle Live have all come under attack from viewers.

A Comedy Roast - a new format imported from America in which Jimmy Carr and fellow comedians 'honoured' Bruce Forsyth, Sharon Osbourne and Chris Tarrant via some close-to-the-bone gags - received over 80 complaints.

Commenting on the Sharon Osbourne episode, one viewer said: "I am an adult and found no humour in this puerile rubbish, only cringe-worthy insults. [It was] car-crash TV that I watched with increasing incredulity, then increasing anger, waiting for the non-existent humour. Like Sharon Osborne, I am unfazed by 'F-ing-and-blinding', I am not easily shocked... but this programme, in my opinion, was highly offensive and not funny in the least. Not the calibre of programming I have come to expect from C4."

A number of people also complained about the humour in the broadcaster's star-studded charity gala, billed as the largest stand-up show in UK history, which was broadcast on the channel on the 5th April. Viewers questioned whether the humour in Channel 4's Comedy Gala was appropriate, given that the event was fundraising for Great Ormond Street Hospital. One viewer wrote in to say: "You ran a comedy show the other night to help raise money for sick children. Unfortunately the show was wall to wall 'adult' and sick humour. I thought this was totally inappropriate for the cause it was associated with. Even the brief tour of the hospital was treated as a joke - and this was supposed to be the serious subject behind the humour. Poor programming."

Perhaps unsurprisingly, a broadcast of Frankie Boyle's 2008 stand-up tour has also come under criticism from some of Channel 4's more conservative viewers.

One comedy fan appeared to be oblivious of Boyle's reputation to shock, and thus was offended by the comic's jokes. The viewer said: "I was looking forward to Frankie Boyle's great comedy and I am so disappointed in the fact he has done nothing but be offensive, to everyone on the planet. Racism, sexism, a complete lack of compassion to serious major world events. It has been abhorrent and although I was warned to be aware of his material, I had no idea how foul he could be. I will be following up how disgusted I am."

It should be noted that the number of complaints about all three of the programmes mentioned above - although higher than average - are actually a relatively small number, given the audience ratings the comedies achieved. For example, of the 3 million plus viewers who watched Channel 4's Comedy Gala, it was only 111 people who contacted the channel afterwards to complain about the language.

On a more positive note, the broadcaster has revealed that viewers have also been in touch to praise some of its comic output. It's long-running comedy drama Shameless received support, with one viewer commenting that a recent episodes was "one of the most amazing pieces of British television I have ever seen". There was praise for Comedy Lab pilots Penelope Princess of Pets and Happy Finish too. Talking about the latter of the two, a sketch show pilot written by The Dawson Brothers, one viewer said "I loved the recent Happy Finish programme as part of the Comedy Lab. Was quality all the way through, well written and cleverly structured and made me roar with laughter at most of the sketches."

The network is also celebrating today, because Channel 4's Alternative Election Night, a four hour live comedy show broadcast on the channel last night with hosts Jimmy Carr, David Mitchell, Lauren Laverne and Charlie Brooker was a ratings hit. Early statistics suggest over 1.5 million viewers watched the show, which means the channel beat both ITV and Sky in the ratings war.

A Channel 4 spokeswoman said: "Our aim was to provide a genuinely original alternative to the usual election night TV, and we're delighted that viewers responded by coming to the show, particularly younger viewers (who are the most difficult to engage with political coverage)."

There is no news yet on which, if any, of the Comedy Lab pilots will be commissioned by Channel 4, or whether there will be another series of A Comedy Roast, but we do know the broadcaster is committed to another series of Shameless and another Comedy Gala next year. Plus, following Frankie Boyle's departure from Mock the Week, the network is reportedly currently working on a new comedy show that will be presented by the controversial stand-up star.