Activist investor Nelson Peltz has upped the pressure on Cadbury Schweppes as today it sheds light on what progress it is making.

The group confirmed that Trian, Mr Peltz's investment vehicle, had indicated that it had increased its stake in the company to about 4.5 per cent from 3.47 per cent previously.

In a statement, Cadbury said it understood the instrument through which the increased interest is held was not reportable and it had not received formal notification in writing.

However reports suggest that Mr Peltz has teamed up with the Qatar Investment Authority to boost his stake in the group and keep the squeeze on the UK drinks and confectionery group to keep on improving its financial performance.

It was claimed Trian had recently formed a special purpose vehicle with the QIA, which it has used to buy derivatives contracts to lift its holding.

Cadbury was this morning issuing a full year trading statement.

Mr Peltz and others have been blamed by critics for supposedly pushing Cadbury into actions like announcing the shutdown of its Keynsham plant in Bristol in 2010 while pushing more work out to Poland.

Angry unions claim the plant is profitable. Jobs will also go at Bournville in Birmingham although Cadbury is investing heavily in the site.

Mr Peltz is widely seen as being the main driver behind Cadbury deciding earlier this year to separate its confectionery and US beverages, although the group has always vigorously denied that it was pushed into the move by his stakebuilding.

Aged 64, Mr Peltz, who has built a reputation for purchasing stakes in businesses and forcing through operational change, took a holding of just below three per cent in Cadbury on March 13, immediately sparking rumours that he would attempt to convince the board to split up the business to realise value for shareholders.

Cadbury confirmed its intention to do that just two days later, following discussions between chief executive Todd Stitzer and Mr Peltz, even though it had categorically ruled out such a move at its full year results presentation on February 20.

"We also consider that Peltz forced management to more aggressively focus on improving its operating margins from the ten per cent that we had previously described as embarrassing," said Sanford Bernstein analyst Andrew Wood.

The shares have had a "roller-coaster" year, rising from 545 pence before Mr Peltz's bid was announced, up to 724 pence in May, and then down to 535 pence in August.