The number of polygamous relationships among British Muslims is increasing, according to British Muslim groups. So what is it like to have two wives or be married to a man and share him with someone else?

"I love both of them. Obviously you can love one more than the other.

"I spend one day and one night with one, and one day one night with the other," says Imran (not his real name), one of the growing number of second generation British Muslim men who have two wives.

Imran was born and brought up in Birmingham, where he runs his own successful business manufacturing Indian desserts.

His first marriage was arranged at the age of 18. However, seven years into the marriage Imran says he fell in love with someone else.

Instead of having an affair he did the honourable thing in the eyes of Islam and married her - thus taking a second wife.

It's better than a man being married and then having mistresses on the side when we can do it legitimately and it's perfectly allowed Imran, Birmingham polygamist

"It's better than a man being married and then having mistresses on the side when we can do it legitimately and it's perfectly allowed," he says.

"God has created us the way we are, that mankind desires more in wealth in sexual desires.

"The main thing is as long as you are 'just' among them, Islamically what can be more right than that, if you are taking care of them, fulfilling their rights," he says.

But Imran did not tell his first wife that he had taken a second wife.

His first wife lives with her in-laws. Imran admits the relationship between his second wife and his parents - who are originally from Pakistan, where monogamy is the norm - is at times strained.

Initially, Imran didn't tell his first wife he had remarried, but eventually she accepted it and now she gets on with his second wife. The wives regularly go shopping together with all his children.

He has four children with his first wife and two with his second wife.

And Imran says a number of his friends now also have second wives too.

Khola Hassan, a lecturer in Islamic Law and volunteer on the UK Sharia Council says she has witnessed a sense of a right to polygamy develop particularly amongst third generation British Muslims.

When she was growing up in Britain 20 years ago she says no-one talked about polygamy as it was incredibly rare. However in the last 15 years she has noticed more polygamous marriages taking place.

It is not known exactly how many British Muslims are involved in polygamous marriages. As they are illegal they are not being officially recorded.

Bigamy is a criminal offence which for those convicted could mean a maximum jail term of up to seven years.

To avoid this, Muslims already legally married instead have a religious ceremony known as a Nikka, which is not registered as a civil marriage, but rather recognises the union in the eyes of Allah.

When a Nikka breaks down or someone wants a divorce, it is the UK Sharia Council some Muslims turn to.

Its 2010 figures show while domestic violence is the most common reason for divorce cited by women, polygamy is now the ninth most common.

But it is not only men who are choosing to live in a polygamous relationship.

Aisha (not her real name) works for the NHS, has her own semi-detached house in Birmingham and is a divorced mother of three girls. Eight months ago she became a second wife after having a Nikka ceremony.

We sat down and I just said I want to be a second wife Aisha, Married in a Nikka ceremony

Her first marriage broke up after she discovered her husband had been having an affair. But three years later she had an affair with a married man.

Her new partner wanted to divorce his first wife and marry Aisha. But she had another idea.

"(I said) 'I don't want to be with you 24/7. I appreciate you want to leave your wife but I don't want you to leave your wife'.

"But he said 'I want to be with you. I want to be married to you'. So we sat down and I just said I want to be a second wife."

Her husband had to break the news to his first wife who was very unhappy with the situation but eventually agreed to it rather than divorce.

He agreed he would still support his first wife and their children, but she in turn said she did not want to know anything at all about Aisha, and she certainly did not want to become friends with her.

Aisha's wedding ceremony was very small and held at home, and not all of Aisha's husband's family even know about her. She says it works well most of the time.

"I have asked my husband if he loves his first wife, and he does say 'I do care about her' and yes he loves her as well.

"That's the only time I do get jealous, but she was there before me, and you know I didn't want to take that away from her.

Image caption Some Muslim women want nothing to do with their husband's second wives

"I've not totally taken him away from his first wife."

Khola Hassan's research has shown her that there are predominantly three types of men who are involved in polygamy.

"There are the radicals, the orthodox who think polygamy is compulsory, almost sense of bravado or competition - 'oh he has second wife and I haven't'," she says.

"The second group are those who have been forced into unhappy marriages usually to cousins from abroad, tried to make the marriage work, have children, and don't want a divorce as their parents will never speak to them again, so have taken a second wife.

"Then there are those who have got a parent living abroad and want someone to look after them."

Sheikh Ibrahim Mogra, a member of the Muslim Council of Britain, says polygamy is something Islam permits as it is in the Koran.

He says in the chapter on women, one verse details how men can marry up to four wives at any one given time.

The situation came about in the 14th Century when there was a battle in which many Muslim men were killed, resulting in many widows and orphans.

In order to safeguard their property and wealth it was suggested other men should marry them.

But according to Sheikh Ibrahim Mogra there is more context which some Muslims are choosing to ignore.

The Koran goes on to say if a man cannot treat his wives fairly, justly and equally then he can only marry one woman.

Although Sheikh Ibrahim Mogra is not against polygamy, he believes in reality very few men can treat even their first wife equally and justly.

"The moment it becomes secretive, or you start treating one less well than the other then you are contradicting the conditions that the Koran sets out.

"And if it's purely done for sexual gratification then that in itself is not a valid reason," he says.

Listen to the Asian Network Report Special: What's Wrong with Polygamy? on Monday 26 September at 18:00.