A method of manufacturing a mineral fibre thermal insulation product comprises the sequential steps of: Forming mineral fibres from a molten mineral mixture; Spraying a substantially formaldehyde free binder solution on to the mineral fibres, the binder solution comprising: a reducing sugar, an acid precursor derivable from an inorganic salt and a source of nitrogen; Collecting the mineral fibres to which the binder solution has been applied to form a batt of mineral fibres; and Curing the batt comprising the mineral fibres and the binder which is in contact with the mineral fibres by passing the batt through a curing oven so as to provide a batt of mineral fibres held together by a substantially water insoluble cured binder.