Do you enjoy Economics? Enough to want to study Economics only over the next 3 years? What are your career plans?
Do you prefer understanding the various aspects of business? From operations research/management to accounting & finance, marketing, human resource management, business development, change management? Do you know what kind of careers are available to business degree graduates?
Economics may be more respectable but so is a business or management degree from respectable universities like Manchester, Warwick, Bath, Bristol, Birmingham, Lancaster, Durham and many more.
You should take into account the other factors in making the final decision. Excellent universities offer business degrees for a good reason. But, in general, I find many people not understanding that a management degree is not about the kind of management one learns on the job. It is a lot more academic and science than just gut feel which is why many underestimate a business degree.