HALTON council leader Tony McDermott has claimed the future of the borough lies with Merseyside rather than Cheshire.
Yesterday the borough signed a deal to become the only authority outside Merseyside to join the Mersey Partnership.
The historic deal means Widnes and Runcorn will join a drive to put the region on the international stage.
And the partnership, made up of local authorities, Government agencies and businesses, yesterday unveiled an ambitious blueprint for change over the next four years.
The planned centrepiece is a 70-mile long Mersey Waterfront Regional Park taking in Halton, Liverpool, Wirral and Southport.
A second venture will see a national centre for biotechnology in Speke.
The waterfront park, including Halton, will be marketed across the world as an advantageous place to invest in and the centre at Speke, together with the laboratories at Daresbury, will ensure Halton remains on the map as a centre for scientific research.
Cllr McDermott said: 'Halton has always been very much a part of Merseyside and now we can develop an even closer relationship as part of the Merseyside Partnership.
'Over recent years, Halton has developed stronger and stronger links with Merseyside and as a result many people, including myself, see Halton as Merseyside's sixth borough.
'Even the vision document we have signed as part of the Mersey Partnership refers to Merseyside being six, not five, local authorities.
'Historically, Halton is part of Cheshire, but we have far more in common with Merseyside and I now believe that is where Halton's economic future lies.'
But Cllr McDermott denied he wanted Halton to sever all links with Cheshire.
He said: 'Our links with Cheshire are historic and important and we want to maintain them. But by the nature of our geographical location, Halton is always going to be close in every way to Merseyside.