Lars Ulrich co-founded the rock band in 1981

A Swedish couple have run into trouble with authorities for trying to name their baby Metallica.

Michael and Karolina Tomaro are locked in a court battle with the country's National Tax Authority about naming their daughter after the rock band.

The six-month-old has been baptised Metallica, but tax officials have dubbed the name "inappropriate".

Under Swedish law, both first names and surnames need to win the approval of authorities before they can be used.

Offensive, unsuitable or inappropriate names, as well as those that could "cause discomfort for the one using it" cannot be used.

Last month, Goteborg's County Administrative Court ruled there was no reason to block the name, adding that a Swedish woman already has the middle name Metallica.

Name battle

However, the Tomaro family ran into trouble when they tried to register the name with tax authorities before applying for a passport.

Tax officials objected to the decision, sending the case to a higher court.

"We've had to cancel trips and can't get anywhere because we can't get her a passport without an approved name," said Mrs Tomaro.

Baby Metallica is not the first Swedish child to fall foul of Swedish name laws - the names Ikea and Veranda have also been rejected in the past.

The name Brfxxccxxmnpcccclllmmnprxvclmnckssqlbb11116 - pronounced Albin - was also rejected by authorities in 1996. The boy's parents had chosen the name as a protest against Swedish naming laws.

But, the name Google managed to pass muster in 2005, when Oliver Google Kai was named by his parents, search engine expert Elias Kai and his wife Carol.