Self-destructing Singleton Inheritance

[goocreations]

I've been trying to implement a super class that is a self-destructing template-based singleton.
The purpose is that I have a singleton that automatically destructs if it is no longer used. I've managed to do that, but now I want to create a super class which you can easily inherit. Here is what I currently have:

@/******************************
Singleton super class
******************************/

template<typename T>
class Singleton : public QObject
{

public:

static T* instance()
{
if(mInstance.isNull())
{
mInstance = QSharedPointer<T>(new T());
}
return mInstance.data();
}

protected:

static QSharedPointer<T> mInstance;

};

template<typename T>
QSharedPointer<T> Singleton<T>::mInstance;

/******************************
Singleton sub class
******************************/

class MyClass : public Singleton<MyClass>
{

protected:

friend class Singleton<MyClass>;
MyClass();

};@

This code might seem "funny", but it works and eliminates the need to re-implement the instance function in the subclasses.
The only problem is that I need this statement:

@friend class Singleton<MyClass>;@

since Singleton uses the protected constructor of the sub class.
Any suggestions on how I can change/improve my code so that I don't need a friend?

[pritamghanghas]

I dont think you can do away with that.
I can add a few more things which dont help the cause but makes it more readable
Your Singleton class need not be a subclass of QObject.
You final class doesnt have to drive from singleton. User of the class can simply say
SIngleton<MyClass>::instance() and you will get the same effect.

[goocreations]

Yes, I don't need to inherit from QObject, this was just to accomodate signals/slots. But it doesn't matter here.

Yes, Singleton<MyClass>::instance() will also work, but I want to encapsulate that. So a programmer can simply call MyClass::instance(), without even knowing/worrying about a super class (aka Singleton).