The two organisations today announced that the ILM, which supports legacy professionals and has about 300 charity members and more than 500 individual members, is consulting members on the proposal, which was described in a joint statement as a merger.
Under the plan, which has the backing of both boards, the ILM would be dissolved as a company and its three members of staff would join the IoF, which employs 40 people.
The ILM would become a special interest group of the IoF, which collectively elect one person to join the IoF board. The ILM branding would be maintained under the new SIG.
ILM members will be asked to vote on the proposals at an extraordinary general meeting, which is expected to take place by the end of May.
If they support the move, the initiative is expected to be completed in the summer.
Helen Hoare, chair of the ILM, said the idea, which was initiated by the ILM, was "born out of our desire and duty to provide our members with the best possible services and support and to promote a wider understanding and appreciation of legacy management across the third sector and beyond".
She said: "The new structure will allow ILM to deliver more to our members with greater efficiency and focus and, most importantly, without losing our strong sense of community."
The two organisations said that the proposal would mean that ILM best-practice guidance could be integrated into the IoF’s Code of Fundraising Practice, leading to one code that would cover the whole of legacy fundraising and management.
The proposal has been supported with £20,000 of funding from the Office of Civil Society and a further contribution, from the Esmée Fairbairn Foundation, the amount of which the IoF was unable to confirm on Friday morning.
Mark Astarita, chair of the IoF, said the move would "properly bring legacy management within the wider fundraising community. This will lead to a more coherent and efficient approach in relation to legacy fundraising, legacy management and awareness campaigning in relation to legacy giving. We hope in the long term this will lead to greater revenue for charities through a more coordinated and joined-up approach to legacy fundraising."
- The story was clarified on 25 April 2014 to make it clear that the IoF's special interest groups elect one representative to the IoF's board