ITV is scrapping late booking fees and will approve campaigns up to the month of transmission until at least the end of 2020.
It follows the broadcaster consulting with ISBA and its members, and is the latest move to stimulate a sluggish advertising market amid the coronavirus outbreak.
ITV said its new policy means that advertisers who stick to their original advanced-booking deadline (usually nine weeks) will retain benefits such as daypart, centre breaks, break position, programme choice and discounts, according to the deal they have in place.
However, those bookings made after the original deadline will no longer be subject to late charges but may lose the guarantee of the benefits listed above.
ITV broadcasts shows including Coronation Street, Emmerdale, Britain’s Got Talent and The Voice.
Earlier this year, when the effects of Covid-19 began to come to light, ITV axed late booking fees and offered a 23% discount for any new campaigns booked for April and May.
The advertising market has been suffering since the outbreak took hold in March as many major brands dropped or paused their marketing spend, however many of these have now returned.
Kelly Williams, managing director for commercial at ITV, said: "This change in approach to ABs is a major shift, and we hope it makes ITV a significantly more flexible partner for advertisers. We’re really grateful to ISBA for their support on this new policy, and we’ve been hugely encouraged by their positive response.
"It’s a perfect example of how we intend to deliver on our ambition to become business partners, not just media partners. And it’s a great example of how we aim to support partners under ITV's new 'Backing Business' initiative."