A Conservative MP has apologised after he posted an Islamophobic image with the head of the London mayor, Sadiq Khan, on a inflatable pig.

Michael Fabricant, the MP for Lichfield, tweeted the “offensive, highly inappropriate and racist” cartoon that also showed the pig engaged in a sexual act with another pig.

It appears alongside an image of the US president Donald Trump, with the comment: “Breaking news: Trump defeats Sadiq Khan in balloon wars.”

Mr Fabricant, who deleted the post shortly after tweeting it out to his 28,000 followers, added: “Well, what can I say.”

His remarks came after Mr Khan, who is Muslim, refused to block a plan by activists to fly a giant inflatable “Trump baby” over Parliament Square on Friday to coincide with a major demonstration in the capital against the US president’s official visit to the UK.

Responding to criticism from the senior Tory Sayeeda Warsi, who reposted a tweet which said “Islamophobia isn’t funny”, Mr Fabricant replied: “Sayeeda – the picture is vile. As soon as I saw what it was, I deleted it. I’m liberal and not anybody-phobic.

“I had been on TV saying that I thought the blimp was hypocritical and when someone sent me the pic[ture] on my iPhone I thought it was a flying pig humping the Trump blimp.”

He later added: “I did not see the detail on my small iPhone. I stupidly tweeted it in a meeting without checking properly and hadn’t spotted there was a face on it.

“I am genuinely sorry if it caused offence and I am disappointed in the person who sent it to me in the first place.”

Responding to the image Afzal Khan, the shadow immigration minister, said: “The Tories have ignored countless calls for an inquiry into Islamophobia in their party from their own members, the former chair of the party and the Muslim Council of Britain.

“Clearly there’s a problem, and if Brandon Lewis’s respect meant anything, Michael Fabricant would be suspended.”

The Labour MP, Wes Streeting, added that he had written to the government’s chief whip, requesting action is taken against the Tory MP for “his offensive, highly inappropriate and racist” post on social media.