Compared to the high-jinks of last year - and the mischief of Prince George and Savannah Phillips - the royal kids were a pretty well-behaved lot at this year's Trooping the Colour.

Perhaps last year's antics were in part why the Cambridge children stood on the other side of the balcony to their cousins?

That said, there were a few cute moments, mostly because of a scene-stealing Prince Louis who was VERY exited at the RAF flyover.

Thanks to the enthusiastic and adorable toddler, we were also treated to one "mum moment" between him and the Duchess of Cambridge which many a parent will be able to relate to.

The thumb's gone in! (
PA Images)
Little Louis looked tired at one point (
PA Images)

The one-year-old prince was spotted sucking his thumb while on the Buckingham Palace balcony.

Noticing that her youngest was indulging in this habit, Kate then gently removed his thumb from his mouth - and the youngster didn't seem best pleased.

It wasn't the first time Louis has been spied, thumb in mouth.

She gently removes his thumb (

Earlier in the day, the youngster was seen peering out of one of the palace windows, again sucking his thumb.

Neither George nor Charlotte have ever been spotted doing the same, but it's a pretty common habit for babies and small children to develop.

Most children are believed to "kick the habit" by the time they're four or five, although some will continue to do so at night.