THE father of missing chef Claudia Lawrence said the new year will bring no let up in his campaign to find his daughter, adding: ''I will never give this up.''

The last nine months have seen Peter Lawrence's world turned upside down as the 63-year-old solicitor has made continual appeals for help to find the university chef who has not been seen since March 18.

Now he is facing up to 2010 and a new series of emotional challenges, not least Claudia's birthday in February.

Mr Lawrence says he is hoping his daughter's 36th birthday on February 27 will provide a new focus for the search. And he is asking for suggestions from anyone who may have a good idea about how to mark the day.

He said: ''We will keep the campaign going. We will never give up until we find Claudia.

''Everyone has been very supportive. Wherever I go across the country, people in the street let me know they are supporting the campaign.

''I will never give this up.

''I believe my daughter is still alive - the hope is just as strong.

Mr Lawrence said his daughter's birthday will be ''another difficult occasion''.

Claudia Lawrence, whose parents are from Darlington and was brought up in Malton, North Yorkshire, was last seen near her home in Heworth, York on March 18. She was reported missing after she failed to arrive to work at a kitchen at York University the next day.

Family and friends had no explanation for why the bubbly and friendly 35-year-old disappeared.

Later, police said they were treating the case as murder and admitted they were examining her relationships with a number of men which Detective Superintendent Ray Galloway, who is leading the inquiry, described as ''of complexity and mystery''.

Earlier in December, Mr Galloway said: ''I am absolutely certain that somebody knows something.''

The detective said the information coming to his officers had reduced from a ''flood to a trickle'', but there remained ''positive lines of inquiry to pursue''.

Mr Galloway said Miss Lawrence's mobile phone had still not been found. He said the university tried to contact her at about 10am on the morning she failed to turn up for work but it went to voicemail. Just after noon on Thursday March 19 it ''detached from the network''.

Mr Lawrence says he is determined to carry on his campaign despite the emotional toll it is taking on him. He says he is strengthened by the support he has received, which has included massive internet contributions on Facebook and through the dedicated site www.FindClaudia.co.uk.

Mr Lawrence has also had the unstinting support of his friend and advisor Martin Dales.

Mr Dales is also determined to keep Miss Lawrence's continued disappearance in the public consciousness in 2010 and believes her birthday will be another key date.

He said plans for a Claudia Awareness Day on her birthday were under way for an event in York on February 27 and another in London on the day before.

''The idea for the day has come from her friends and members of the general public who through Facebook, emails and FindClaudia.co.uk have expressed their desire to want to do something to help keep Claudia's profile raised across as wide an area as possible,'' said Mr Dales.

''Although, we are still in the early stages of planning and already have some ideas, we would very much like to hear from people with their own ideas so that as many people as possible can be involved and be a part of this special day.

''In order to make this happen, we are also seeking partners and wish to engage support both from individuals and from the national, regional and local business and corporate communities as we hope they will wish to be associated with her father, Peter's, untiring efforts to campaign and not rest until Claudia is found.''