REPORTS suggest the second royal baby could be imminent after rumours circulated the Duchess of Cambridge has gone into labour.

It was reported she went into hospital on national radio earlier today with the buzz growing over the past few hours that Prince George could soon have a little brother or sister.

And with the Queen celebrating her actual birthday today it could mean an extra special present of a new great-grandchild.

But Kensington Palace is yet to make any official announcement confirming or denying the reports.

Prince William has begun his paternity leave from his job as a trainee rescue helicopter pilot, further fuelling the rumours the new baby could be well on the way.

Sources had suggested that William might have to make a dash from flying training with his employer, Bond Air Services, to be with Kate if she went into labour.

But he is now on leave from his job until June 1, when he will start a final three-week phase of work before beginning to fly rescue missions with the East Anglian Air Ambulance charity.

Kate is expected to give birth in the coming days and is likely to be at her London home, Kensington Palace.

A Kensington Palace spokesman said: ''The Duke of Cambridge has completed the first phase of his in-work air ambulance helicopter pilot training with Bond Air Services earlier than anticipated.

''This is due to a combination of the Duke performing well in the various modules and having very good flying conditions that allowed flight training and assessment to progress more quickly than had been planned. 

''His final block of in-work training requires an uninterrupted three-week block of working time and the availability of the new EC145 helicopter that will be used for missions. 

''This has always been scheduled to commence on 1st June, following a pre-planned period of official royal engagements in late May, details of which will be announced in due course. 

''As he now will not have any further training to complete after returning from paternity leave, he will not return to duties with Bond until that time, and will remain on unpaid leave until then.''