White will take the reins of an 18-strong department as head of corporate communications from the end of June. Since the departure of Debra Leith two years ago, the position has been covered by commercial director Mark Keene, to whom White will report.
Her new role at PITO, which supplies information technology to police forces, is to oversee internal and external communications, marketing, media relations and database management.
She said: 'It is a customer-focused organisation and I see my role going in there to develop a corporate comms service that supports PITO in its business.
'At Westminster, I was dealing with city and issues management on a daily basis. My new role will be more strategic and gives me an opportunity to use a wider range of skills,' she added.
White first joined Westminster six years ago as senior marketing manager. She was seconded to the Greater London Authority from March to August 2000 before the first mayoral elections. On returning to Westminster, she took up her current post, which gave her responsibility for the five-strong press office and press operation.