LONDON (Reuters) - The United States’ first tax overhaul in decades may not pass Congress until well into 2017, House of Representatives Speaker Paul Ryan said on Wednesday, in a sign the timetable for the legislation has been pushed back. Revamping the U.S. tax code has become a new legislative test for President Donald Trump after a Republican push to repeal former President Barack Obama’s signature healthcare law failed last month in a humiliating defeat for the party. Some Republicans in Congress had hoped to pass the tax overhaul before August, but party divisions over the legislation and difficulties in replacing Obamacare have slowed the process. “This will be done in 2017, that is our time line, we would like to get it done as soon as possible,” Ryan told reporters during a visit to London that was part of a multi-nation trip aimed at strengthening U.S. economic and security ties with NATO allies. Ryan added: “As soon as possible for us is by the end of summer but we’re going to take our time to get it right. We can clearly get this done by the end of summer but if it needs to go a little longer, we’ll do that.” Trump made tax reform a core campaign promise, saying he would simplify the tax code and cut tax rates in ways that could significantly increase government debt.  To tackle the biggest overhaul of the U.S. tax code since the Reagan era, House Republicans need to avoid the political fault lines that sank their healthcare bill, partly by having conservatives on board. Ryan has been pushing a plan that includes a border adjustment tax, or BAT, that would levy a 20 percent tax on imported goods. The provision has been attacked by some conservatives and Democrats who argue it would hurt consumers and some U.S. companies reliant on foreign goods. The Senate has been awaiting action by the House before considering tax legislation. Given the Republican divisions, the White House has said it would submit its own tax proposal to Congress but it was unclear when that might arrive. Treasury Secretary Steven Mnuchin said this week that tax reform may not get done before an August deadline.  The Trump administration might also include a $1 trillion infrastructure investment plan in whatever tax bill it submits to Congress. 