WHEN you've already built a time machine in your backyard, what's next?

That's the question that Gowrie Junction father Mark Anderson faced after he built Doctor Who's iconic big blue box a couple of years ago.

The answer came to him one rainy Friday afternoon - a giant Lego 11th Doctor.

"It had to be Matt Smith's Doctor," he said.

"He was the Doctor of the moment when the kids got interested in it."

He said while the 11th Doctor was the one he shared with his children Logan and Casey, when he was a child he would rush home to watch Tom Baker's 4th Doctor.

Construction started with the head and once he found a gas bottle of a suitable size, he got to work creating the rest of the body out of steel.

"It's a 30:1 scale and it probably took about 80 hours work and weighs about 300kg," he said.

Mr Anderson said it was the hair that took the most work and was made out of solid bars.

"I was originally going to just put him in the yard, but I thought let's make him a letter box," he said.

It's not just Doctor Who that's given him inspiration for his creations, although Mr Anderson said he does plan on building a moving Dalek and putting lights and sound effects in the TARDIS in the future.

"I'm making a dragon at the moment," he said.

Official Lego Doctor Who sets will be released sometime this year.