"In Islamic Sharia, rape is adultery by force. So long as the woman is his wife, it cannot be termed as rape," The Independent quoted cleric Sheikh Maulana Abu Sayeed as saying.
Men accused of raping their wives should not be prosecuted as "sex is part of marriage", said Sayeed, president of the Islamic Sharia Council in Britain.
He made the comments to the blog The Samosa -- and reiterated them to the The Independent.
Sayeed told the website: "Clearly there cannot be any rape within the marriage. Maybe aggression, maybe indecent activity... Because when they got married, the understanding was that sexual intercourse was part of the marriage, so there cannot be anything against sex in marriage.
"Of course, if it happened without her desire, that is no good, that is not desirable."
British law makes rape within marriage illegal.
Sayeed also suggested that women who claim to have been raped by their husbands should not immediately go to the police.
"Not in the beginning, unless we establish that it really happened. Because in most of the cases, wives... have been advised by their solicitors that one of the four reasons for which a wife can get a divorce is rape, so they are encouraged to say things like this."
Asked how men found to have raped their wives were to be punished, he said: "He may be disciplined, and he may be made to ask forgiveness. That should be enough."
Muslims4UK's chairman Inayat Bunglawala said: "Sheikh Sayeed's comments are woefully misguided and entirely inappropriate. Rape - whether within marriage or outside it - is an abominable act and is clearly against the law."
Dave Whatton, spokesman on rape for the Association of Chief Police Officers, told the daily: "We know that the majority of rapes do not take place through strangers attacking women late at night but between acquaintances and within marriages and partnerships.
"It is a fundamental principle that Sharia law should not replace the laws of the UK.
Putting out views that rape can be dealt with in another way fundamentally undermines everything we are trying to do," he said.