Prince Charles's excuse that he flies by helicopter to lecture people on carbon emissions because he's busy is ‘bizarre'.

That's according to campaign group Republic - which has previously analysed Charles's travel and engagements - when responding to reports that Charles flew by helicopter to and from Cambridge to give a lecture on climate change.

The official royal website shows Charles had no other engagements on the day he flew by helicopter to and from Cambridge, where he lectured on the need to reduce our carbon footprints. 

Graham Smith, speaking for the group, said today:

"Charles had no other official engagements that day. So why the hurry in getting from one place to another?"

"Charles claims to have been to 521 engagements last year. At about one hour each that's less than four months of work in the year. Spread out across twelve months that's nobody's idea of busy."

"Our previous analysis shows most of those events events are at or very near Highgrove, Clarence House or Balmoral."

"I think most people holding down busy jobs would be surprised to hear a few meetings is an excuse to fly by helicopter". 

"Charles is not serious about the environment if he continues to ignore his own impact on the environment. Offsetting carbon doesn't make up for the huge impact his travel has on air pollution."