A liner (10) for fitting within a headcap to provide a degree of impact protection, said liner comprising a generally concave shell for receiving a wearer's head, in use, and having a top section (16), a front section (12) and a rear section (14), and a pair of side panels extending downward from, and integrally formed with, respective side edges of said top section (16), wherein a first slot (14a) is provided on each side of said rear section (14), extending from a side edge thereof to a hinge portion (14b) located between said top portion (16) and said rear section (14), and a second slot (12a) is provided on each side of said front section (12) extending from a side edge thereof to a hinge portion (12b) located between said top portion (16) and said front section (12).