The UK Mountain Leader award
The Mountain Leader (ML) award from Mountain Training covers leading groups in the hills and mountains of the UK and Ireland in summer conditions: navigation, group management, emergency procedures and mountain weather. Winter conditions need the separate Winter Mountain Leader award.
The International Mountain Leader (IML)
The IML is recognised by UIMLA, the Union of International Mountain Leader Associations, and qualifies the holder to lead treks in mountains worldwide on non-glaciated terrain, including hut-to-hut routes such as the Tour du Mont Blanc. National equivalents include the French Accompagnateur en Montagne (AMM) and the Italian Accompagnatore di Media Montagna.
Mountain leader vs mountain guide
An IFMGA mountain guide holds the highest mountain qualification and can lead glacier travel, alpine climbing, ski touring and roped terrain. A mountain leader covers walking and trekking terrain. For a marked hut-to-hut trek a mountain leader is the right professional; for a glaciated summit you need a mountain guide.
Related questions
Can a mountain leader take you on a glacier?
No. Glacier travel and roped climbing are outside a mountain leader's remit and require an IFMGA mountain guide.
Is a mountain leader the same as an AMM?
Broadly, yes. The French Accompagnateur en Montagne (AMM) is a national mountain-leader qualification, and AMM holders can join UIMLA as International Mountain Leaders.