MEBYON KERNOW leader Dick Cole has called on Cornish representatives of national political parties to help support a bid for more powers to be devolved to Cornwall.
He urged more support to be given to the transfer of powers from Westminster to the regions, including Cornwall.
In the St Piran's Day message, he said: "Last year, the people of Wales voted overwhelmingly to increase the powers of the Welsh Assembly, and the Scottish Nationalist Party won a clear majority in the Scottish Parliament.
"There will therefore be a referendum on Scottish independence in 2014.
"There is clearly a desperate need for a mature, respectful and wide-ranging debate about the future of the whole of the United Kingdom, and how it is governed, and surely now is the time to address the unequal constitutional relationships between the various nations and regions of the UK, and to tackle the centralising influence of London and the South- East of England.
"It is to be welcomed that some MPs in the North of England are again seeking directly elected regional government for the north, but here in Cornwall, even our political integrity and territoriality is under threat, with central government planning to impose a cross-Tamar constituency."
Mr Cole has written to local members of the Conservatives, Liberal Democrats and Labour urging them to support MK's decentralisation campaign.
"We need to put Cornwall at the heart of the debate about the future governance of the United Kingdom and achieve the meaningful devolution of political powers to Cornwall," he said.
Twitter users gave maximum exposure to St Piran's Day when the phrase "Happy St Piran's Day" soared up the trending chart on the social media site.
It matched the position achieved by the second most mentioned phrase in the UK and also scored highly on worldwide trending charts as Cornish people all over the world marked the occasion.