Should Ipswich Borough Council spend £3million on doubling the size of the Crown Car Park – or go the whole hog and quadruple it at a cost of about £12m?

That’s the choice that is set to be discussed by borough members early next year when a final decision on the future of the site will be made.

There are two options up for discussion. One is building a prefabricated single-deck extension to the current car park.

That would double its current capacity of about 230 vehicles – providing a total of 450 spaces. The work would take several weeks to complete and would cost about £3m. It could be open in time for Christmas next year.

The prefabricated structure would be “semi-permanent”, similar to that at Manningtree station, but could be moved in future years if the site needed to be redeveloped.

The second option is for the construction of a permanent 900-space multi-storey car park which would cost about £12m. Work on that would start in early 2017 and it would be open by Christmas that year.

However the costs of the work are the major issue. The council could easily find the £3m – it would only require a 60% increase in the number of users of the car park.

The full multi-storey would need to see a 220% increase in the number of users – while maintaining current prices – and to justify that work the council would need guarantees of financial support.

This could come from retailers helping to sponsor the work, from town centre businesses agreeing to buy a substantial number of parking season tickets for their employees – or by a combination of the two.

A final decision will be made at February’s meeting of the borough’s executive.

Council leader David Ellesmere said: “My preference would be for the full rebuild – it is the long-term option and would be seen as a clear vote of confidence in the town centre.

“However the cost would represent a considerable risk for the council and we would need extra support if we are to go ahead with that.

“The cost of the single-storey option would be much easier to justify and would have virtually no financial risk.”