If you are off sick with back strain, even for a short period, you may not be able to return to your original job straight away. The laws prohibiting disability discrimination (now contained in the Equality Act 2010) impose a duty on employers to make 'reasonable adjustments' for people with disabilities.
If your employer is not sympathetic or helpful, you might be better off going to the next meeting with a fellow worker. You have the right to be accompanied at meetings with management.
The TUC has called for employers to be legally required to have a rehabilitation policy framework in place. See the TUC webpages on rehabilitation.
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