A 7 per cent fall in Brent crude oil prices kept energy costs low last month, despite increased wholesale prices for gas, electricity and coal.

Analysts say an easing of geopolitical tensions in Syria and Iran drove the fall in crude oil prices.

However natural gas wholesale prices increased by 4 per cent in September due to supply constraints from planned maintenance and a bout of cold weather.

The Bord Gáis Energy Index for last month fell 3 per cent in September at 143, its first month-on- month drop since June.

According to Bord Gáis trader John Heffernan: "The ongoing rise in wholesale UK day-ahead gas prices was of particular note. The prolonged gas demand in the winter of 2012-2013 influenced prices throughout the summer months as market participants replenished depleted stock levels amid heavy summer maintenance and reduced supplies.

“This results in summer trading levels for wholesale gas which will influence prices in the months ahead.”