[citation needed] From the outset, the channel suffered poor viewing figures and its main backer, Invest TV Resources, withdrew their support in March 2001.

Lewis also presented "Money Saving Expert" slots on Channel 5's daytime show, Open House with Gloria Hunniford.

In 2012, he began co-presenting The Martin Lewis Money Show, initially with Saira Khan, and more recently with Angellica Bell.

[16] In 2024, Lewis was announced to appear as a contestant in the "New Year Treat 2025" special of Taskmaster, alongside David James, Hannah Fry, Melanie Blatt, and Sue Johnston.

[20] In July 2015 Lewis sold just over half his shareholding in Moneysupermarket.com, obtained in the sale of Money Saving Expert, for £25.2 million.

"[25] In late 2005, campaigns against what were claimed to be unfair bank charges gained momentum and a few small websites started to highlight the issue.

Lewis was at the forefront of the media campaign to reclaim what he states are unfair and unlawful fees charged by UK banks.

He presented the first mainstream television programme on how to reclaim bank fees (ITV1's Tonight) and in November 2006 published a step-by-step guide, including template letters as well as regularly appearing across the media to champion the issue.

[26] His campaign suffered a major setback in November 2009 when the Supreme Court of the United Kingdom ruled that the charges imposed by banks formed part of their fees for current account services and could not be assessed for fairness under the Unfair Terms in Consumer Contracts Regulations.

[27] Lewis, along with other consumer groups, hired Ray Cox QC (a barrister with previous experience of banking cases)[28] to look into new legal arguments for account holders wishing to reclaim charges, which might possibly use regulation 5 of the Unfair Terms Act as suggested by the Supreme Court Judgement.

[29] This attempt suffered a further setback when, on 22 December 2009, the Office of Fair Trading (OFT) issued a statement saying that it had decided against taking forward such an investigation because it "would have a very limited scope and low prospects of success".

In summer 2008, Lewis appeared on several television and radio programmes exhorting consumers to "cap your energy bills now", based on the prediction that there would be a further round of price increases at the end of 2008.

Information published by uSwitch, a price comparison site whose business motivation is to encourage frequent switching between energy suppliers, after the price cuts, in February 2009, suggested that "Those who were savvy enough to sign up to a competitive fixed-price plan last summer, before some increases in wholesale energy were passed on, are sitting pretty as prices would need to drop by 16% on average before it would be worth moving"[33] but failed to be clear about which specific capped deals it was basing this assertion on, and when it was sensible to have committed to a capped rate deal.

[34] After subtle changes to student loan repayments were announced in the Autumn Statement of 2015, Lewis appealed directly to the Prime Minister and engaged lawyers to investigate.

[36] Lewis' other large-scale campaigns, with ensuing television programmes, include refunds for missold payment protection insurance.

[citation needed] In November 2023, he was ranked number four in the New Statesman's Left Power List, described by the journal as "having the casting vote" over who can fix the national economy.

[46] The Economist magazine has called Lewis "one of Britain’s most recognisable figures" and possibly "the most influential man in British politics".