As previously reported upgrading key routes such as the A77 and A75 would boost the local economy and improve links to Northern Ireland through the ferry terminals at Cairnryan.
The UK Government’s Union Connectivity Review, which is examining how to improve transport links across the United Kingdom, had been asked to consider a bridge or tunnel across the Irish Sea.
While Prime Minister Boris Johnson was reportedly supportive of the idea, there were concerns from some quarters that the engineering required for the structure would be too complex and poor value for money.
Now it seems the plans have been parked after reports that the costs of building a bridge or tunnel would be too large.
However, Mr Whittle says that regardless of how goods and people cross the water, the roads to and from the coast still need investment.
He has now challenged the Scottish Government to improve the roads and deliver a package of investment that supports the economy and the environment by upgrading the A77 and A75 with electric vehicle charging and hydrogen fuelling infrastructure.
Mr Whittle said: “A physical link between Scotland and Northern Ireland would have had its benefits, but the costs and practicalities of such a scheme always meant it was unlikely to happen.
“That doesn’t change the clear need for investment in the road links to the existing ferry terminals.
“The A77 and A75 are holding the area back and need investment to help the economy flourish.
“The Scottish Government refused to participate in the UK G overnment’s Union Connectivity Review and, despite their warm words to local residents about future investment, have joined a coalition with the Scottish Greens that threatens future road investment.
“I’ll continue to campaign to improve the A75 and A77, and make the so uth west’s transport links fit for the 21st Century with proper infrastructure for electric and hydrogen vehicles.”