No. But you can't rent to your spouse if that's what you're getting around to. A married couple can only have a single PPR so one can't be renting from the other.
PS. I am assuming you are asking from the point of view of a PPR owner considering using the rent a room scheme and not as a potential tenant of a rent a room property.
Lenders won't take rent a room income into account for couples (married or not) - they assume the couple would want, ahem, their privacy! There's no rule to say you can't let room(s) however.
No no, one of my friend is getting his mortgage approval, he is married and is looking to purchase 3 bed property. He is a first time buyer. In order to get good mortgage I suggested him to inform the lender that he will rent out a room. But his lender informed that he is not eligible for rent a room as he is married.
As SarahW says this is most likely a lender decision rather than a Revenue restriction on who can avail of the scheme. See [broken link removed]:
The relief is available to individuals only. It does not apply to companies or
partnerships. However, it can apply where individuals have the income jointly
(for instance husband and wife where there is no partnership), there the limit
can be divided between the individuals concerned. Individuals who rent as
well as individuals who own their own home may avail of the relief.
If he intends living in the property then he is entitled to the rent a room relief irrespective of marital status.
I suspect that the lender is taking the view that - since he is married it is unlikely that your friend will continue to rent out the room for very long. Hence the lender does not want to take the rent-a-room income into account for the mortgage application.