Oliver Duff said the Saturday edition’s “unwelcome” 20p price boost was a reflection of the increasing cost of raw materials, which he said had risen sharply to a point at which publisher Johnston Press needed to pass some of the cost onto readers, according to a report by Press Gazette.

He said demand for newsprint was increasing from overseas publishers that were also prepared to pay higher prices. PrintWeek reported that various paper merchants were issuing letters outlining increases of up to 8% last week as the result of mill notifications. The soaring price of pulp was cited as the main driving force.

With both the i and its weekend counterpart printed at the printing facilities of Johnston rival Reach – formerly Trinity Mirror – rising costs were also pegged on the increase in energy bills, with gas prices rising by 21% since April and electricity by 18%.

Johnston Press group publishing director Richard Thomson said: “Johnston Press buys its paper from two paper mills in the UK and from Canada, Germany, Belgium, Norway, Finland and Sweden. This year brought two price increases, and the first was at the beginning of the year when currency and supply were the major factors in the price increase of around 8%.

“That meant an increase in costs of around £600,000p.a. Buying paper in an international open market place means the newsprint industry is dependent on the pound performance. A weaker pound caused the mills to increase prices to try and align with prices being paid in Europe and USA. In addition, our UK suppliers are now selling more paper abroad to get higher prices and this has put pressure on our supplies and price.

“We have negotiated competitive pricing with our paper suppliers to help alleviate the inflation impact, however other raw materials such as oils and pigments used in inks and printing plates use aluminium which has also had a price increase of 10%.”

Newspaper sales at Johnston Press fell by 1.9% in the publisher’s half-year results for 2018, from £39.6m to £38.9m. The i was shown in the results to have generated £18.6m in adjusted EBITDA for Johnston since acquisition, with £6m in H1 2018 alone.

With the price increase, iWeekend is now more expensive that the Daily Express’ 90p Saturday paper and on par with the Daily Mail.

The i had a total circulation of 243,940 in ABC figures from July, down 9% year-on-year, although its digital audience continues to grow. Duff cited a “deluge of free (and often low-quality)” online articles as a key challenge for his newspaper.