Da Vinci challengers will appeal

The authors' copyright claim was rejected in April

Two authors who lost a copyright battle against best-selling novel The Da Vinci Code earlier this year have been given permission to challenge the verdict.

The authors' lawyers said the appeal had "a real prospect of success".

Michael Baigent and Richard Leigh claimed author Dan Brown had copied ideas from their 1982 book, The Holy Blood and The Holy Grail.

No date has been set for the hearing. However, it is expected to take place later this year or in early 2007.

The High Court ruled in April that Brown had not copied the other two writers.

Both books explore the theory that Jesus and Mary Magdalene had a child and the bloodline survives to this day.

Random House - publisher of both The Da Vinci Code and The Holy Blood and The Holy Grail - said it acknowledged the right of Baigent and Leigh to appeal.

"We regret, however, that more time and money is being spent trying to establish a case that was so comprehensively defeated in the High Court," a spokesman told Reuters news agency.

The Da Vinci Code has sold 40 million-plus copies worldwide, while the other book has sold more than two million.