WHILE completing any marathon is a remarkable achievement, some 26.2-mile races demand far more from runners than others.

From punishing climbs and relentless terrain to unpredictable weather and strict cut-off times, a number of factors can make reaching the finish line significantly more challenging.

New research by Betway has ranked the toughest and easiest road marathons in the UK, analysing 27 predominantly road-based events using criteria including elevation gain, cut-off pace and typical weather conditions.

While the Isle of Wight Marathon topped the list as the UK's most difficult marathon with a score of 67.1 out of 100, Marathon Eryri secured third place and was recognised as the most mountainous race in the entire study.

Set against the spectacular backdrop of Eryri (Snowdonia), the iconic Welsh event recorded a staggering 797 metres of elevation gain, comfortably the highest among the leading marathons analysed. The route's demanding climbs, combined with often challenging mountain weather, help cement its reputation as one of Britain's toughest endurance tests.

Runners taking on Marathon Eryri also contend with some of the wettest conditions in the study, with rain recorded on an average of 60.3% of race days, adding an extra layer of difficulty to an already punishing course.

Only the Isle of Wight Marathon and Jersey Marathon ranked higher overall, with both races benefiting from considerably lower elevation gains but facing difficult coastal conditions and stronger winds.

The findings reinforce Marathon Eryri's long-standing reputation as one of the UK's premier marathon challenges, attracting runners from across the country eager to test themselves on a route renowned for its scenery, atmosphere and relentless climbs.

Other demanding events highlighted in the study included the Windermere Marathon, with 600 metres of climbing, and the Langdale Marathon, which recorded the greatest elevation gain overall at 1,035 metres.

The easiest marathons

At the opposite end of the rankings, the London Marathon was rated the easiest marathon in the UK based on the factors analysed, scoring 16.7 out of 100. Its largely flat route features just 75 metres of elevation gain, while generous cut-off times and generally favourable spring weather conditions contribute to its lower difficulty rating.

Brighton Marathon ranked second easiest, followed by the Shakespeare Marathon, Manchester Marathon and Boston Marathon UK, all benefiting from flatter profiles and more forgiving race conditions.