One of the things I’ll be doing on the blog over the next few months is taking a look at each region of the UK to see how significant a role they’ll play in the general election.

Inspired by last week’s local by-election results, I’m starting with south-west England: the area of the country where the contest between the Tories and the Liberal Democrats could be the most ferocious, and where Labour barely gets a look-in.

I’m defining the south-west as the following counties and/or unitary authorities: Bath & NE Somerset; Bournemouth; Bristol; Cornwall; Devon; Dorset; North Somerset; Plymouth; Poole; Somerset; Torbay and the Isles of Scilly.

This gives a total of 39 parliamentary constituencies. Here’s how they are currently distributed between parties:

Here are some of the region’s key electoral statistics:

• Number of marginals (sitting MP has a majority under 5,000): 23, or 59.0% of total

• Number of ultra-marginals (sitting MP has a majority under 1,000): 5 or 12.8% of total

• Conservative targets: 11 (all from Lib Dem)

• Labour targets: 2 (both from Conservative)

• Lib Dem targets: 8 (all from Conservative)

With over half of its seats counting as marginals, the south-west could be one of the regions of the UK that sees the greatest turnover over MPs in May. It also means it is in for a lot of visits from senior politicians, celebrities and the media during the campaign.

Liberal Democrats

South-west England could be where the Liberal Democrats suffer their greatest cumulative setback. The region plays host to over a fifth of the party’s entire total of MPs – and up to nine of those are at risk. Here are the Lib Dem seats and the current majorities:

In each of these seats bar one (Bristol West), the challenging party is the Conservatives. We’re very much in traditional Lib Dem-Tory territory here.

The high profile MPs tend to be those in the safer seats – David Laws in Yeovil, for example, and Nick Harvey in Devon North. Stephen Williams will hold on in Bristol West, while Don Foster is standing down in Bath. I’m sure there’ll be a fair few Lib Dem hopefuls jostling to inherit his majority of just under 12,000.

Labour

Labour has maintained a toehold in south-west England thanks to the three big cities of Exeter, Plymouth and Bristol. Nonetheless its four MPs should all be safe at the election:

The Tories are Labour’s main challenger in each of the seats except Bristol South, where the Lib Dems are in second place. Ukip’s impact on these contests will be minimal in the university cities of Bristol and Exeter. It may draw votes from both parties in Plymouth, but I’m going to say that this won’t be enough to lead to a Labour defeat.

Conservatives

On paper, at least four Tory seats in the south-west ought to be easy pickings for the Lib Dems. In reality I wonder if they will win any extra seats at all in May, let alone off the Conservatives. Here’s the full list of the 23 Tory seats in the south-west:

A few big names here, but none are in marginal seats. The former defence secretary Liam Fox is MP for Somerset North; Sarah Wollaston, recently elected chair of the Commons health select committee, is MP for Totnes; Jacob Rees-Mogg is the MP for Somerset North East.

The Tories ought to hold almost all these seats at the election. Even George Eustice will win again in Camborne & Redruth, despite having one of the tiniest majorities in Great Britain. That’s because the Lib Dems are the party in second place.

Only Plymouth Sutton & Devonport should change hands, where Labour needs a 1.3% swing to take the seat.

Of more consequence will be how many of those Lib Dem marginals the Tories are able to vacuum up, and hence offset against losses to Labour elsewhere in the country.

The south-west could be the region where the Tories make the most number of gains in the election. But they will be in vain unless the party is able to replicate such an aggressive performance against all its rivals at the polls, and not merely the Liberal Democrats.