The deflation gripping the UK grocery sector shows little sign of easing as supermarket prices remain more than 2% lower year on year, according to the latest Grocer Price Index.

Collated by Brand View from more than 60,000 SKUs across the big four, the headline GPI figure remained almost unchanged - moving to -2.12% in the month to 1 October from -2.15% in the previous months.

The GPI has remained virtually unmoved for the past three months and has recorded deflation of more than 2% in five of the past eight months.

Once again, all of the big four recorded annual price deflation. Sainsbury’s saw the biggest annual price drop during the month, with shelf prices dropping by an average of 2.9%.

While the overall deflation picture has remained stable, who is offering the steepest cuts keeps changing. This month’s top cutter, Sainsbury’s, is the third new top cutter in three months, following Tesco in the month to 1 September and Morrisons to 1 August.

The heavy price cuts of the listed supermarkets highlight the efforts they have undergone over the past year to sharpen their price profiles and close the gap to the discounters. Asda, which had a more competitive price position already, has recorded the lowest deflation of the big four for every month since the month to 1 February.

So far this year, Morrisons has seen average monthly price drops of 2.6%, Sainsbury’s of 2.5% and Tesco of 2.2%, while Asda has seen prices fall by a monthly average of 0.7% over the same period.

Waitrose, not included in the GPI figure, saw prices fall by 0.9% last month to take its average price cuts to just 0.3% so far this year.

This month, 13 of 14 GPI categories saw overall price cuts, with only health and beauty seeing inflation, up 0.2%. The biggest year-on-year price falls were seen in bakery (-4.9%), deli (-4.2%) and liquor (-3.7%).

The stability of GPI annual deflation - and month-on-month prices falling by 1.1% in the month to 1 October - shows the tough task facing the supermarkets to turn around damaging sales falls even as the trading performance of the mults is improving.

Year-on-year deflation comparatives may ease over the coming months, though, as deflation especially ratcheted up in the autumn of 2014. The month to 1 November 2014 was the first time annual deflation ran above -1% and it has not been below that figure since.

Even if the GPI figure starts to edge back closer to zero over the coming months, supermarket bosses are convinced deflation will remain for some time.

Sainsbury’s CEO Mike Coupe said he did not expect deflation to abate until the early part of 2016 at the earliest, while Tesco CEO Dave Lewis this week said there was “more deflation to come” and he didn’t see market conditions changing in the short term.