In the Generations For Generations project, the two charities teamed up with a single message to win support from supermarket chain Morrisons for both ChildLine and SeniorLine.
It was the second award of the night for the NSPCC, which also won Best Donor Development Campaign for a campaign to win back lapsed donors. The campaign managed to outstrip its targets by 12.5 per cent.
Fifteen awards were made after a dinner at the Institute of Fundraising's National Convention, held in London. Other winning campaigns included Comic Relief, which won the Best Use of E-Media prize for a Sport Relief email campaign that raised just under £112,000, and Friends of the Earth's Mighty Oaks direct mail campaign to encourage people to leave legacies, which claimed the Best Use of Legacy Fundraising award.
The Royal Parks Foundation won the Fundraising Team of the Year prize for its half-marathon event. Arun Sharma of Marie Curie Cancer Care received the Fundraiser of the Year award for his work on the charity's Tesco Charity of the Year campaign, which has raised more than £5.8m.
The Lifetime Contribution Award went to Judy Beard for a notable career that has included stints at Macmillan, the British Red Cross, the Management Centre and Save the Children.
Kirsty Thomson, head of events at the IoF, said: "The National Awards have shone a spotlight on the very best our sector has to offer. Many congratulations to all of our winners."
The winners in full
- Best Business-Charity Partnership (Large Charities): Oxfam and M&S
- Best Business-Charity Partnership (Small/Medium Charities): SolarAid and Solarcentury
- Best Donor Development Campaign: NSPCC
- Most Innovative Fundraising Campaign: NSPCC and Help the Aged
- Best Use of Direct Mail: Royal British Legion
- Best Use of E-Media: Comic Relief
- Best Use of Face-to-Face: Shelter
- Best Use of Legacy Fundraising: Friends of the Earth
- Best Use of Payroll Giving: Beaverbrooks
- Best Use of Telephone: Save the Children
- Volunteer Fundraiser of the Year: Barbara Walmsley, Oxfam
- Best Fundraising Charity to Work For: Clic Sargent
- Gill Astarita Fundraiser of the Year: Arun Sharma, Marie Curie Cancer Care
- Best Up-and-Coming Fundraiser: Cat Kirkcaldy, Community Foundation for Merseyside
- Fundraising Team of the Year: Royal Parks Foundation
- Lifetime Contribution Award: Judy Beard