The British firm decided to go ahead after legislation was changed this week to prevent a planning levy for local infrastructure being double-charged - adding significantly to costs.
"The Bill we are publishing today is all about helping our country compete in the global race and building an aspiration nation where we back those who want to get on life," the premier said.
"We are slashing unnecessary bureaucracy, giving business the confidence to invest, unlocking big infrastructure projects and supporting hard working people to realise their dreams.
"Already the changes we are making to the planning system are having an impact, with Land Securities giving the go-ahead to a major multimillion-pound investment, supporting thousands of jobs in our construction industry."
Land Securities chief executive Robert Noel said: "It is heartening to know that Government has listened to the industry and acted to remove some of the uncertainty in the planning process."