Ms Roberts - who is married to Newsnight editor Ian Katz - said the incident involving her home happened on Tuesday of last week.
"I wasn't actually there - I was on holiday," she told the BBC.
"The first thing I knew was when our au pair contacted us the next morning to tell us that at 03:30 she'd been woken up and disturbed by a Swat team of five armed police and three unarmed police and a police dog.
"They'd received a report of a man prowling round the house with a gun."
She said that she was aware such incidents had become more common in the US, but she believed they remained relatively rare in the UK.
"At first I think the police were slightly nonplussed and said they were not sure, because there were no actual real victims, that it was a pursuable crime.
"But I think in the States it's treated incredibly seriously because, of course, if you get copycat things like this it can be incredibly disruptive, not to mention the cost to the security forces."
A spokesman for the Metropolitan Police provided further details.
"Police were called at approximately 00:15 on Tuesday 11 August to a residential address... following a report that a man had murdered a woman at the address," he said.
"This was followed by a second call during which the caller stated he had members of his family held in a room. This call was assessed as requiring a firearms response.
"Local officers and firearms officers attended the address and carried out an assessment. Two people resident at the address were spoken to. The incident was treated as a hoax and the police response explained to those at the address.
"No suspects have been identified at this time, however enquiries continue."