Anti-monarchy demonstrators taunt royal family ahead of Kate's Trooping The Colour comeback - saying 'it's a lovely day for a protest, join us outside Buckingham Palace!'

Anti-monarchy protestors have taunted the royal family ahead of the Princess of Wales's comeback for Trooping The Colour today.

Republic, a group which advocates abolishing the monarchy, shared a post of activists gathering outside Buckingham Palace ahead of the King's official birthday parade.

It read: 'It's a sunny day (so far) for a protest! Join us, outside Buckingham Palace from 9.00am.'

It comes a crowds arrived to support Kate in her first public appearance this year.

Catherine, who has been receiving treatment for an undisclosed form of cancer, will ride in a carriage with her three children, George, Charlotte and Louis.

She will then appear alongside the King, Queen Camilla and her husband the Prince of Wales to observe an RAF bypass on the Buckingham Palace balcony.

But anti-monarchy protestors were pictured arriving on The Mall before the annual ceremony.

One demonstrator, wearing a yellow Republic top, was seen waving a flag with the message 'not my king', next to royal supporters holding Union flags.

Republic has previously made a stand at major royal events, including at the King's Coronation last year during which several activists were arrested.

It supports removing the monarch and replacing it with an elected head of state.

Its chief executive Graham Smith said that despite disagreeing with the reasons given by police, the restriction was not a 'big problem'.

'We've got quite loud voices', he said. 

Scotland Yard confirmed that the campaign group would be allowed to protest but without amplified sound between 8am and 3pm.

The Metropolitan Police has said hundreds of officers will be deployed on the procession route in a 'substantial' operation to protect visitors, with thousands expected to descend on central London ahead of the pageant.

Visitors wishing to get a sight of the ceremony have been advised to stand either on The Mall or on the edge of St James's Park overlooking Horse Guards Parade from 9am, with the parade due to start at 10am.

The ceremony will also be broadcast on BBC One from 10.30am, with coverage lasting until the flypast concludes at 1pm.

Last night, the Princess of Wales issued a statement saying that she continued to experience 'good days and bad days' on her journey to recovery.

As well as confirming her attendance at today's event, she expressed  hope that she would be able to 'join a few public engagements over the summer', while stressing she was not 'out of the woods yet'.