Health- conscious middle-class Plummer family - who don't drink, smoke or eat junk food - are devastated when they are sent to Menorca for a boozy beach holiday with the working-class Dochertys.
And the Dochertys are equally upset when they are sent to Jamaica with the Plummers, who forbid them to smoke in the house, ban them from drinking - and take them on healthy treks through the rainforest.
The two mums, Kim Docherty and Simone Plummer, almost come to blows after Simone bans Kim from smoking in their luxury villa and asks her not to drink alcohol.
Tearful Kim, shouts: "Okay, I'm getting seriously p***ed off now. Why can't I have a drink? It's my holiday too. I don't like it when people tell me what I can and can't do. If you tell me I can't smoke, I'll light up right now."
It ends with Kim storming up to her bedroom in tears, shouting: "If I light a fag and she says anything I will f***ing punch her. I'm going to smack her one, the stupid bitch."
The huge showdown comes after days of bickering. During the first week of the holiday swap the Dochertys from East London - Kim, 38, market trader Danny, 42, Kerry, 15, and Jamie, 12, - take the Plummers to Menorca for a week of drinking, karaoke and lounging by the pool.
Although the children in both families get on well, friction between the adults is apparent almost immediately - and a crisis meeting is called just two days into the holidays.
Singer and songwriter Simone moans: "We haven't been out of the complex in 48 hours. Making us stay in one place for the whole time is not enjoyable for us."
Husband James says of the resort: "It's extremely tacky. It's full of Northerners - like Blackpool in Spain."
And by the second week, in Jamaica, the arguments start to get really heated.
The Plummers from South East London - Simone, 44, dad James, 48, and children Aliyah, 13, and Jay, 12 - have rented a luxury villa which comes with its own cook.
Their idea of holiday heaven is to go for a long walk to a waterfall. James describes it as "paradise" but Kim retorts: "It's horrible, bloody horrible." At the end of the holiday, Dave sums up the experience: "It's nice in Jamaica, but I could go to East London and have a better time with real people.
"If I wanted a time like this, I'd go to a clothes shop and sit with the mannequins. They don't eat either."
