A letter campaign contacting thousands of pensioners across the West Midlands urging them to renew their concessionary travel passes has proved a success.

But transport bosses say they are still anxious to hear from pass holders who have yet to respond.

A total of 126,000 older people whose passes expire on March 31 are in the first wave of nearly half a million holders to get replacements issued by Centro, the region’s transport authority.

So far a total of 93,000 people have renewed and Centro said while it was delighted so many had responded it was keen to hear from more than 30,000 holders who have passes that expire on March 31 but have not yet been in touch.

Sarah Jones, Centro’s Head of Customer Services, said: “These passes are a real lifeline for people and while there is still plenty of time to renew them we would urge anyone who has received a letter but not yet responded to contact us.

“Similarly, if you have not received a letter but have a pass that expires on March 31 we would like to hear from you.

“Our dedicated helpline is available between 9am and 5pm Monday to Friday and we can easily renew a travel pass over the telephone.”

The English National Concessionary pass was introduced in 2008 and provides free off-peak travel on buses across England for older people.

Centro administers the scheme locally on behalf of the Department for Transport.

The concession is enhanced within the West Midlands with free, off-peak travel on trains and trams across the region.

The original smart passes will expire in four batches - March 2012, August 2012, March 2013 and April 2013 and Centro is currently processing the March 2012 renewals.

Renewal letters have not been sent to blind and disabled pass holders as a separate process applies to these customers.

Centro writes to these pass holders, whose continued eligibility for a travel pass has to be reassessed, three months prior to their passes expiring.

A dedicated telephone line to respond to enquiries about renewals is available between 9am and 5pm Monday to Friday. The number is 08450 755 888.