With just five weeks to go until Britain goes to the polls for what Prime Minister David Cameron has called the most important General Election in a generation.

The impact of May 7th's vote won't just be felt in the United Kingdom and is likely to shape Anglo-Irish relations for years to come. 

Irish voters

The financial crisis of 2008 saw tens of thousands leave these shores. 90,000 of them went to our nearest neighbour.

This is nothing new. An estimated one million people across the UK were born in Ireland and 345,000 Irish are eligible to vote on May 7th.

In fact, you could argue that the British General Election is therefore the biggest election involving Irish voters outside of our own borders. 

That right to vote for Britain's next Government, which is reciprocated to UK citizens living here, is a rare privilege and gives the Irish a unique status in what is a diverse landscape. Despite recent fears that the right to vote would be withdrawn from immigrant groups, British Government spokespeople have emphasised their high regard for the special status of Irish-born voters in the elections.

A large number of these will be migrants from previous generations - the labourers and their families who moved to cities like Liverpool, Manchester, Birmingham and are synonymous with areas of London like Cricklewood and Kilburn. That batch of migrants is now ageing rapidly, so issues like the future of the NHS and pensions will be among their chief concerns. 

Anglo-Irish relations

Ties between recent Irish and UK leaders have been cordial.

Bertie Ahern and Tony Blair's famous rapport gave them a formidable grounding in the Good Friday Agreement negotiations and we were all reminded of former Tory PM John Major's deep respect for Albert Reynolds when he attended the late Fianna Fáil Taoiseach's State funeral last year. 

These strong working links coincided with some of the most productive eras in Anglo-Irish relations. 

Ahern and Blair set up the British-Irish Council to help foster a closer relationship between the governments across these islands. However, successors Gordon Brown and David Cameron have been less inclined to take part in proceedings.

Official Ireland will be hoping that, whomever the next Prime Minister may be, closer ties with Ireland will still have some place on the agenda.

The North - "You can always do a deal with an Ulsterman"

David Cameron may start to pay closer attention to the North in the coming weeks, however. The Democratic Unionist Party, set for at least 6 of the North's 18 seats in Westminster, could be key to keeping him in Downing Street.

As Conservative elder statesman Kenneth Clarke once put it, "you can always do a deal with an Ulsterman, but it's not the way to run a modern, sophisticated society". 

The DUP itself has made no secret of its glee at the opportunity to play "kingmaker" by propping up either a minority Government. 

If a Unionist bloc in Westminster cosies up to David Cameron (or Ed Miliband for that matter), it will at the very least see the incoming Prime Minister viewed with some degree of suspicion in any Northern talks by Sinn Féin and the SDLP.

If the DUP's support is called upon, party leader Peter Robinson is likely to present a "shopping list" of demands in return.

The bottom line here is tax. The Stormont Assembly has long sought more control of the North's finances and would want to have power over the air passenger levy and, most importantly, corporation tax. A move which may see the North put some pressure on the Republic and compete for foreign direct investment.

That would be a concern, no doubt, but there's a far bigger worry on the horizon... 

The Brexit

Britain and Ireland have always had strong trade links but these have been furthered significantly since both nations joined the European Union. 

Over €1 billion is traded in goods and services between the two countries every single week. 42% of our food and drink exports, a whopping €4.1 billion, went to the United Kingdom in 2013.

Factor in the freedom of movement between EU members, the endless family and personal links and it becomes extraordinarily clear why the Taoiseach has identified a British retreat from Europe as "catastrophic" for Ireland. 

There's a problem. 46% of Britons say they'd vote to take the UK out of Europe and David Cameron has committed to a referendum on the UK's future membership of the Union by 2017.

His intention here is to put the onus on Brussels to accommodate Britain's demands for reform and return more control over immigration, the free market and energy policies to Westminster.

It may not be quite as simple as that. His feet may be held to the fire by Nigel Farage and UKIP, who would demand a referendum as early as Christmas with the intention of ending over 42 years of EU membership.

If Enda Kenny's worst fears become a reality, and the UK turns its back on the European project, the first impact would be closest to home. 

A 'hard border' of passport checks and customs officers would return along the frontier with the North as British authorities look the prevent immigration through the back door across the UK's only land border with the EU.

In fact, the fear about the economic consequences of a 'Brexit' runs so deep on Merrion Street right now that the Department of the Taoiseach is reported by The Irish Times to have set-up a group preparing for the impact to our businesses.

A lurch to the right and UKIP would induce winces and worries in Government quarters.

While it'll be a long night for David Cameron, Ed Miliband and co on May 7th, you can bet it'll be equally sleepless for Enda Kenny and his officials.