Martin Freeman has "smacked" his kids in the past

He confessed: "I have smacked my kids. When they were very young. I smacked my kids, yes. And it's not like a victory. It's not, 'Oh, I must be doing something right!' But I have done it. When it is route one to something they need to understand and I cannot rationalise with them. Also I was impatient and at the end of my rope."

The 'Sherlock' star says he knows it's "a good idea not to hit your kids", but wants to be honest about his past so he can be upfront with his children when they're older.

He added: "Obviously, it's a good idea not to hit your kids. But at some point you're going to do things wrong and, 20 years on, your kids are going to ask why you did that. It's inevitable. And with smacking - I'm not proud I did that, but I have. I don't think it's a policy."

And Martin also thinks it's important to understand the distinction between "the odd slap" and abuse.

The 'Breeders' actor said: "I was never hit, but I know plenty of people who were, and they don't really b***h about it now. It's different if you get the sh**t kicked out of you, but the odd slap? I know plenty who don't care."

Martin lashed out at the idea of perfection in modern parenting, and says he often feels "like a failure" when things aren't perfect.

Speaking to The Sunday Times' Culture magazine, he said: "That is another frustrating thing about parenting, and what makes you feel like a failure. All the images we're getting about how to parent if you're a nice, arty person are a series of rules we all either adhere to or pretend to. You know, positive affirmation and everything is great, and you're perfect the way you are. Well, you're not. One of the rules is, don't smack your kids or call them little f***ers.

"But, you know, I've done both. I've probably smacked twice, but I've called them little f***ers more then twice. I know I'm not supposed to do it, but there are so many images about how [parenting] all just has to be brilliant that it makes people feel bad. Because it's not brilliant. I mean, it is - it's the best thing I'll do. But that doesn't mean it's not really hard."