where i work we are all salaried, but our employer wants to pay us ssp when we are off sick, can he do this or must he pay us our normal wage for being off sick???
Are you saying your employer is proposing to change your T&cs of employment when sick to remove normal pay and replace it with just SSP?
If so, that's a change that should be discussed with all employees to explain the reason (or negotiated with a Union, if Union recognition operates on the site).
Being salaried doesn't imply any entitlement to sick pay (more than SSP) when off sick. And the SSP bit comes from the Governement anyway.
Sick pay (beyond SSP) is not a legal entitlement and hence your employer is within their rights to operate like this.
However, as buidlersmate identifies, if you already have a contract which states that you do get paid sick leave beyond SSP then to change it the Company should go through consultation about the contractual amendment.