The delivery of the Queensferry Crossing project has been given a clean bill of health from Audit Scotland for being managed effectively and delivering value for money, though a clearer plan is needed to measure its wider benefits.

The £1.34 billion bridge across the Firth of Forth came in almost £250 million under budget when it opened a year ago, though its completion came eight months later than first estimated.

A new report from Auditor General Caroline Gardner found that the infrastructure scheme was managed effectively.

Her report praises Transport Scotland’s budgeting, governance, quality assurance and risk management - as well as the competitive tendering which helped deliver the project under budget.

A key factor behind the project’s success was that the delivery team had the right mix of skills and experience.

“They demonstrated strong, consistent leadership, and communicated well with contractors and stakeholder groups,” the report said. “The government identified a clear need for the bridge, and demonstrated that the preferred option - a cable-stayed bridge - had several advantages over other options and designs.”

The spending watchdog said it is too early for some of the project’s wider benefits - such as improving public transport across the Forth, cutting journey times, and boosting economic growth - to be demonstrated. But more detail is needed on how success will be measured.

Ms Gardner said: “There is much the public sector can learn from the way Transport Scotland managed the project and it’s important that the good practice is shared more widely.

“The management of the project delivered value for money and achieved its overall aim of maintaining a reliable road link between Fife and the Lothians.

“Transport Scotland now needs to produce a clearer plan about how it will measure the success of the project’s wider benefits, including its contribution to economic growth and improved public transport links.”

Transport secretary Michael Matheson welcomed the report’s findings and said a full post-project evaluation was planned for later in the year.

He said: “While it is too early to complete a wide-ranging assessment evaluating the project’s outcomes, we accept the recommendations in the report and aim to carry out a full post-project evaluation in late 2018 detailing performance relating to journey times and traffic flows.

“This will include an assessment of the impact of improved network connections and junctions, and the project’s contribution to economic growth and exploring what further support can be offered to public transport providers to meet any future increase in demand for travel across the Forth.”

He added: “As recommended in the report, the successful delivery of the Forth Replacement Crossing project has provided a number of valuable lessons learned that we utilise in our future work and we will seek opportunities to share these lessons more broadly within the Scottish Government and the broader public sector.”