The UK’s competition watchdog could start initial work on its investigations into the actions of US online giants by the end of this year, raising the prospect of further penalties for Big Tech on top of major European fines. Sources familiar with the situation said the Competition & Markets Authority (CMA) was planning preliminary work within the next couple of months to prepare for a possible full investigation shortly after the UK leaves the EU at the end of March. The CMA had been precluded from launching parallel investigations to those being conducted by the European Commission, such as those into Google and Amazon, but after Brexit is likely to secure new responsibilities. Competition lawyers believe the CMA is “obviously thinking very carefully” about how it will police tech companies in future. Speaking at a House of Lords committee last week, CMA chief executive Andrea Coscelli said the UK authority was “focusing on national cases, and cases against Google and Amazon are done in Brussels”. “This is now likely to change post-Brexit. It might change in the next few months, or a little bit later.” The Treasury awarded the watchdog an additional £23.6m for 2017-18 on top of its £68.7m annual budget, recognising the scale of work it will have to take on.