Downhole slip apparatus for boreholes of smaller and of larger diameter

A down hole slip apparatus that includes a radially extendable slip assembly (20). The radially extendable slip assembly (20) including a primary slip arrangement (40) and a secondary slip arrangement (45). The downhole slip apparatus is arranged such that during a first phase of operation the primary (40) and secondary (45) slip arrangements are radially extendable simultaneously from a retracted configuration towards and/or into a first extended configuration. The downhole slip apparatus is also arranged such that during a subsequent second phase of operation the secondary slip arrangement (45) is radially extendable relative to the primary slip arrangement (40) towards and/or into a second extended configuration. A downhole slip apparatus that includes a radially extendable slip assembly. The radially extendable slip assembly including a primary slip arrangement and a secondary slip arrangement. The downhole slip apparatus is arranged such that during a first phase of operation the primary and secondary slip arrangements are radially extendable simultaneously from a retracted configuration towards and/or into a first extended configuration. The downhole slip apparatus is also arranged such that during a subsequent second phase of operation the secondary slip arrangement is radially extendable relative to the primary slip arrangement towards and/or into a second extended configuration.