By Guy Faulconbridge and Ritvik Carvalho

LONDON (Reuters) - The wives of Islamic State fighters ponder what to wear at a beheading and assess how sexy they look in suicide vests in a BBC satire which has sparked both anger and praise for tackling the fate of women who travel to Syria to join the militants.

In a clip from the BBC's "Revolting" TV comedy show, entitled "Real Housewives of ISIS" which aired on Tuesday, one "wife" of a militant fighter in Syria says: "It's only three days to the beheading and I've got no idea what to wear."

"This is my sixth marriage - I have been widowed five times," another woman says with a sigh before an explosion which prompts her to say: "Six times."

For the clip, please see: https://www.youtube.com/watch?v=DOB6UDC-67w

The segment is a parody of the successful reality TV franchise which began in 2006 with "The Real Housewives of Orange County" and now has spin-off versions worldwide including one set in Cheshire in northern England.

The women, dressed in hijabs and speaking with clear English accents, also compare their looks in suicide vests while posting the pictures online but then argue over the fact that their attire clashes as two have the same suicide vest.

"You're gonna need a lot of Semtex to kill that one," one says. While another scrubs the floor, she says: "Didn't have to do this in [the English city of] Birmingham."

Tens of thousands of people have travelled to fight in Syria and Iraq where many end up with militant groups such as Islamic State, which uses an extreme interpretation of Islam to justify attacks on its foes and impose repressive rule in areas it has captured.

Islamic State has used the internet to tempt recruits from across the world, including sometimes well-educated young men and women from British cities.

British police said last January 56 women and girls from Britain had gone to Syria and there have been several high-profile cases including three schoolgirls who left London in February, 2015. One of the girls was reported to have been killed last August.

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"RIGHT TO SATIRIZE"

IS demands what it calls proper Islamic behaviour for citizens of its self-proclaimed caliphate but allows sexual slavery of non-Muslim women, and widespread rape of women and girls, according to witnesses from the region.

Under Islamic State's rules, women are required to largely stay at home or wear head-to-toe black coverings if they venture out. The internet, music and cell phones are banned.

In one scene in the BBC satire, a woman parades a chain that ties her to a cooker: "Ali's brought me a new chain which is eight foot long so I can almost get outside, which is great."

The short clip elicited millions of views on social media and sparked a debate about whether such satire was appropriate given the deadly seriousness of ISIS.

"Bad taste, not funny at all," posted Anna Butcher, who said that victims of ISIS and their families would not laugh at such films. "Sorry why laugh at the thought of woman showing off explosive jackets etc, is sick sorry."

Others defended satire as a way to tackle grave issues.

"This is fantastic...people bang on about politically incorrect humor...this is brave & funny & about time we poked fun at these morons! Even Muslims will love this," Timmy Poncho said on Facebook.

The show was written by directors Heydon Prowse and Jolyon Rubinstein, who defended their satire and said it was targeting online grooming that had enticed thousands to join ISIS.

"It is important not to pull your punches in satire," Prowse said in a statement. "You have to be fearless or it undermines your credibility. You can’t go after [former Prime Minister] David Cameron for five years like we did and not go after ISIS."

The BBC did not immediately respond to a request for comment. Hat Trick Productions, which produced the show, sent Prowse's statement.

"I support and defend the right to criticise and satirize events like this," Oz Katerji, a journalist, told the BBC. "To be honest, I think this is about two years late."

(Reporting by Guy Faulconbridge; editing by Ralph Boulton)