FORTH Ports is facing pressure to invest in the £100 million-plus upgrade of Leith docks after it emerged that comparable work in the north of England is being funded entirely with private money.

The Sunday Herald has learned that the £130m upgrade of the port of Hull is being funded by Associated British Ports (ABP), with no financial input from the public sector. ABP is spending the money to unlock an £80m investment from German group Siemens to build a factory at the port which will assemble nacelles – the central parts of the tops of offshore wind turbines, where electricity is generated.

ABP's investment involves building a circa 630-metre outer berth to allow ships to pick up and drop off turbine parts, and filling in part of the area's Alexandra dock to create more manufacturing space.

As revealed in these pages last week, the latest thinking for Leith to secure a turbine manufacturing investment from Gamesa of Spain and possibly other players is that there will need to be an outer berthing terminal and that Queen Elizabeth dock will be filled in. This is thought likely to cost in excess of £100m.

According to senior sources, Leith docks owner Forth Ports's starting position in any negotiation over payments is likely to be that the public sector should foot at least a substantial part of this cost. Some of this might come from Scottish Enterprise's £80m National Renewables Infrastructure Fund, but it will have to satisfy funding requests from various other Scottish ports, too.

With cash-strapped Edinburgh City Council unlikely to be able to contribute much, it is not yet clear where the rest will come from. The fact ABP is spending without assistance on a competitor port in Hull will put pressure on Forth Ports to invest heavily in Leith, since it will receive rent from any manufacturer that sets up a facility on its land. It also raises the prospect that it will have to contribute to any upgrades at its other ports that are relevant to renewables, including Methil and Dundee.

Mark Lazarowicz, the Labour and Co-operative MP for Edinburgh North and Leith, said: "When infrastructure is upgraded to meet the needs of industrial development, there's always going to be a negotiation about how much will be provided by the state and by companies that will benefit. My view is that all companies that potentially benefit should at some stage provide an input."

The Sunday Herald revealed last week that plans to upgrade the harbour's lock gates had been scrapped after it emerged Leith lacked sufficient turning space to allow vessels to pick up and drop off giant wind turbine parts. The discovery necessitates new plans for a berth terminal alongside the harbour, requiring substantial additional investment.

Forth Ports said negotiations were ongoing but declined to make any other comment.