Member of base class template is out of scope in derived class template with same template argument

The following code gives me a compilation error 'value' was not declared in this scope.

template<class T>
struct Base {
    int value;
};

template <class T>
struct Derived : public Base<T> {
    int getValue() { return value; }
};

I find it extremely odd that

• if Derived inherits from Base<std::string>, the code compiles,
• if I return Base<T>::value, the code compiles.

Why doesn't the code compile as it is? In what way is 'value' not declared in the scope of Derived<T>::getValue()?